Chimeric protein in the treatment of amyloidosis

ABSTRACT

The present invention relates to a chimeric protein comprising at least one human amyloid P component and at least one fragment of an Fc region of a human antibody, the human amyloid P component and the fragment of an Fc region with which it is associated being bound to each other by means of a hinge region.

FIELD OF THE INVENTION

The present invention relates to the field of obtaining a specificchimeric protein for therapeutic use, in particular for treatingamyloidosis, in particular amyloidosis of AL type.

PRIOR ART

Amyloidosis is a vast group of diseases belonging to the group ofprotein conformational diseases encompassing other diseases such as, forexample, Alzheimer's disease, transmissible spongiform encephalopathies,Huntington's disease or type II diabetes.

Amyloidosis is a rare disease which is characterized by the presence ofdeposits of insoluble proteins which adopt an abnormal fibrillarconformation in the tissues. Most commonly, it is serum precursorprotein fragments which are the cause thereof. Many organs can beaffected by these extracellular deposits, called “amyloid substance”.The main organs affected by the amyloid deposits are the kidney, theheart, the digestive tract, the liver, the skin, peripheral nerves andthe eye. The organs affected by this disease generally have a sizeablevolume. In fact, amyloidosis can involve all the organs, and also thecentral nervous system, so that there are numerous very varied symptoms.

Amyloidosis is a severe disease which can progress to destruction of theaffected organs. There are more than 25 proteins capable of formingamyloid deposits.

It is generally accepted that amyloid substance is approximately 90%composed of fibrillar proteins which are characteristic of each varietyof amyloidosis. Among the remaining 10%, approximately 5% are composedof glycosaminoglycans (GAGs) and 5% are composed of glycoproteins calledamyloid P component (or SAP protein), SAP being constantly presentwhatever the type of amyloidosis.

Table 1 hereinafter lists the main types of amyloidosis. The latter arenamed according to the nature of the protein involved, which itself willbe denoted by the prefix A (for amyloidosis) and a specific suffix.Thus, amyloid protein derived from immunoglobulin light chains isdenoted AL, and the amyloidosis consisting of these chains is called “ALamyloidosis”; likewise, for the ATTR proteins derived fromtransthyretin, the corresponding amyloidosis is called “ATTRamyloidosis”.

TABLE 1 Amyloidosis nomenclature and classification Amyloid Syndromes ortissues protein Precursor Spread affected AL Ig light chain (κ, λ) G, L(Primary) isolated or associated with myeloma or with Waldenströmdisease AH Ig heavy chain ( 

 ) G, L Isolated AA apoSAA G, L (Secondary) infections, chronicinflammations, tumors, TRAPS, FMF, Muckle and Wells syndrome ATTRMutated transthyretin, G Familial senile Normal transthyretin G Chronicβ2-Microglobulin G Associated with terminal renal insufficiency Aβ2MAAρoA1 Apoliproprotein A1 G Familial aortic (intima) L AAρoA2Apoliproprotein A2 G Familial AGel Gelsolin G Familial ALys Lysosym GFamilial AFib Fibrinogen G Familial ACys Cystatin C L Familial cerebralhemorrhage Aβ Aβ protein precursor L Alzheimer's disease, (AβPP) trisomy21, familial or sporadic cerebral amyloid angiopathy APrPsc Prionprotein precursor L Spongiform encephalopathy ACal Procalcitonin LThyroid medullary cancer AANF Natriuretic atrial factor L Isolatedatrial amyloidosis AIAPP Amylin L Islets of Langerhans of type 2diabetes, insulinoma Alns* Insulin L Lactrogenic APro* Prolactin LProlactinoma, pituitary gland senile AKep* Keratoepithelin L Latticecorneal dystrophies Abri* BRI-L L Familial British dementia ALact*Lactoferrin L Seminal vesicle Amed* Lactadherin L Aortic (media) FMF:familial Mediterranean fever; TRAPS: tumor necrosis factor (TNF)receptor-associated periodic syndrome; Ig: immunoglobulin; G:generalized amyloidosis; L: localized amyloidosis; *non-officialnomenclature. Grateau G. Amyloses [Amyloidosis]. Encyclopédie Orphanet[Orphanet Encyclopedia], May 2001, updated June 2003.

The diagnosis of amyloidosis is based on the identification of theamyloid deposits during anatomical-pathological examination. Ittherefore requires targeted biopsies, but it is more difficult to gainaccess to certain organs or there is a not insignificant risk (heart,brain, etc.) Amyloid substances can be specifically recognized using adye, Congo red, by observing yellow-green dichroic birefringence inpolarized light. They can also be recognized by electron microscopy.Following the identification of these amyloid substances, the use ofspecific antibodies makes it possible to identify the type ofamyloidosis under consideration (Ab against SAA, CL kappa and lambda,fibrinogen, TTR, apoA1, apoA2, lysozyme, Ig heavy chains) (Picken M M.,Current Opin Nephrol Hypertens, 2007; 16: 196; Vrana J A et al., Blood,2009; 114: 4957).

Several approaches for treating amyloidosis can be envisioned, namely(1) elimination of the source of production, (2) inhibition of fibrilelongation or (3) active elimination of the amyloid deposits.

Treating the cause of the production of the abnormal protein (i.e.approach (1) above) is the best means of limiting the progression of theamyloid disease. On the other hand, at the current time, each type ofamyloidosis requires a different treatment.

For AL amyloidosis, the most severe form in which the damage is the mostdisseminated, the treatment consists in reducing the formation of theamyloid substance deposits. For this, it is necessary to inhibit as muchas possible the production of the monoclonal immunoglobulin responsiblefor the deposits. Most commonly, a treatment is carried out bychemotherapy (by administration, in particular, of glucocorticoids(dexamethasone) and of antimitotics). The efficacy of the treatment isevaluated by measuring the reduction in the amount of monoclonal lightchain in the blood. If this reduction is considerable, the amyloidsubstance deposits, the formation of which is inhibited, will begradually eliminated by the organism. This leads to a gradualimprovement in the clinical condition. The rate of elimination of thedeposits is variable depending on the organ and depending on patients,and generally requires several months to be noticeable. At the currenttime, there is no treatment that can accelerate the elimination of thedeposits. AL amyloidosis can be localized or disseminated, asymptomaticor, on the contrary, can have a dreadful prognosis.

In parallel, specific treatments for compensating for the insufficiencyor insufficiencies in terms of operation of the organ(s) affected by theamyloidosis are generally carried out. In the event of the heart orkidneys being severely affected, a transplant may be proposed.

Chemotherapy treatment for AL amyloidosis comprises, however, numerousside effects such as hair loss, diarrhea, nausea or vomiting.Hematological toxicity is the most recurrent and most serious phenomenonand requires constant monitoring of the patient. It consists of adecrease, which may be considerable, in several blood components withsizeable risks: thrombocytopenia caused by a drop in blood plateletswith a hemorrhagic risk, anemia, leukopenia with an infectious risk.

At a very advanced stage of AL amyloidosis, the damage in the organs issuch that chemotherapy is ineffective. A transplant is then necessary.

For AA amyloidosis, treatment of the underlying inflammation is the mostimportant therapeutic measure. The efficacy of the new anti-inflammatorytreatments (anti-TNF, anti-IL1) is in the process of being clinicallyevaluated. However, for the moment, this amyloidosis remains incurableand fatal, since there is no specific treatment that can eliminate thedeposits more rapidly.

In transthyretin amyloidosis (familial amyloidosis), a liver transplantmay be proposed for the purpose of eliminating the main source ofproduction of abnormal TTR protein. This treatment has demonstrated itsefficacy in stopping the progression of the disease in the vast majorityof cases of familial amyloid neuropathies treated at an early stage(90%), this being with an average amount of time passed of 8 years.Furthermore, this treatment is not effective when it is begun at anadvanced pathological stage, in particular when there is cardiacinvolvement.

Regarding the treatment approach consisting in inhibiting fibrilelongation (i.e. approach (2) above), it is known practice to use DMSOand colchicine, and I-Dox, anthracyclin interacting with the amyloiddeposits. However, it appears that these treatments, although they causea delay in the appearance of the amyloid deposits, inhibit however theirelongation little or not at all (Merlini G, Blood 93, 1999: 1112).

Regarding the treatment approach consisting in actively eliminating theamyloid deposits (i.e. approach (3) above), it is known practice to usemurine monoclonal antibodies which recognize a conformational epitope ofthe amyloidosis (11-1F4) (Solomon, Am. J. Path., 2000, 157: 1239).However, it appears that these antibodies do not seem to be veryeffective.

Moreover, document WO 2009/000926 proposes the administration, inparticular, of anti-SAP antibodies. This strategy makes it possible torecruit the macrophages and to bring about the elimination of theamyloid deposits. However, the drawback of this strategy is that itrequires a prior step of administering(R)-1-[6-[(R)-2-carboxypyrrolidin-1-yl]-6-oxohexanoyl]pyrrolidine-2-carboxylicacid (CPHPC) so as to eliminate the circulating SAP (Pepys M B et al.,Nature, 2010, 468(7320): 93-7).

Moreover, NEOD001 is a monoclonal antibody in the process of beingdeveloped by Prothena, which specifically targets amyloid substances ofAL or AA amyloidosis type.

This antibody reacts only with the aggregated form of the proteinsresponsible for this AL amyloidosis.

Other alternative therapeutic agents in the treatment of amyloidosis arebeing studied at the current time. In this respect, mention may be madeof tafamidis which appears to make it possible to stabilize thecirculating protein and to prevent deposit formation, doxycyclin whichcould break the amyloid fibrils and prevent deposit formation (alreadytested on animals (Ward J. E., Blood 2011, 118(25): 6610) and in phaseII in humans (Obici L. et al., Amyloid 2012: Suppl. 1: 34)) or elseTUDCA, an anti-apoptosis molecule in the process of being tested.

Consequently, and for obvious reasons, the use of alternativetherapeutic agents that are effective in the treatment of amyloidosisremains a constant objective with, in particular, the need to havetreatments of which the objective is to slow down deposit formation orto accelerate deposit elimination, which in addition is devoid of thedrawbacks mentioned above.

The objective of the present invention is precisely to meet thisexpectation.

SUMMARY OF THE INVENTION

According to a first of its aspects, the present invention relates to achimeric protein comprising at least one human amyloid P component andat least one fragment of an Fc region of a human antibody, the humanamyloid P component and the fragment of an Fc region to which it isattached being bonded to each other by means of a hinge region.

With the proviso of an appropriate architecture, as defined hereinafter,such a chimeric protein in fact takes advantage, on the one hand, of thenatural affinity of SAP for amyloid deposits and, on the other hand, ofthe ability of the antibody Fc region to recruit effector cells, inparticular the neutrophil polymorphonuclear cells and themonocyte-macrophages involved in the elimination of the amyloiddeposits.

Thus, by virtue of the ability of the antibody Fc region to recruiteffector cells, a chimeric protein according to the invention enableseffective elimination of the amyloid substance deposits, thus resultingin an improvement in the clinical condition of the treated patient.

Since SAP is present in all types of amyloidosis, as previouslyindicated, the present invention is particularly advantageous in that itis effective whatever the type of amyloidosis considered, systemic orlocalized.

A chimeric protein according to the invention therefore offers aneffective therapeutic alternative in the treatment of amyloidosis, within addition the advantage of being devoid of the adverse side effectsassociated with the conventional treatments for amyloidosis, asmentioned above.

What is more, contrary to the strategy described in WO 2009/000926, thepresent invention does not require a preliminary step consisting inadministering CPHPC so as to eliminate the circulating SAP.

Finally, the use of material of human origin for a chimeric proteinaccording to the invention makes it possible to guarantee, on the onehand, maximum innocuousness with regard to the patient treated and, onthe other hand, a level of interaction with the optimal targets underconsideration (represented by the amyloid deposits and the effectorcells).

Indeed, the use of human sequences or sequences having a strongsimilarity with the human sequences for a chimeric protein according tothe invention makes it possible to reduce the risk of immunogenicityafter administration, thus ensuring good tolerance of the administeredchimeric proteins by the organism treated.

According to one particular embodiment, the human amyloid P componentpresent in a chimeric protein according to the invention can berepresented by an amino acid sequence having at least 80% identity withthe sequence SEQ ID NO: 1.

According to another particular embodiment, the Fc region of the humanantibody responsible for each of the Fc region fragments considered in achimeric protein according to the invention may be an Fc region of ahuman immunoglobulin, preferably an Fc region of an IgG, preferably anFc region of an IgG1 or of an IgG2, and more particularly an Fc regionof an IgG1.

According to another particular embodiment, the fragment of an Fc regionof a human antibody considered in a chimeric protein according to theinvention may be represented by at least one amino acid sequence havingat least 80% identity with the sequence SEQ ID NO: 3.

According to one particular embodiment, the fragment of an Fc region ofa human antibody considered in a chimeric protein according to theinvention may exhibit an improved affinity for FcRn compared with afragment of an Fc region of a parent human antibody.

In this respect, the fragment of an Fc region of a human antibodyconsidered in a chimeric protein according to the invention may compriseat least two modifications in the amino acid sequence as defined in WO2010/106180, namely:

(i) a modification in the amino acid sequence chosen from the groupconsisting of 378V, 378T, 434Y and 434S, and

(ii) at least one modification in the amino acid sequence chosen fromthe group consisting of 226G, 230S, 230T, 230L, 241 L, 264E, 307P, 315D,330V, 362R, 378V, 378T, 389T, 389K, 434Y and 434S,

it being understood that the numbering of the amino acids of the Fcregion is that of the EU index proposed by Kabat and on the conditionthat the modification (i) does not occur at the same amino acid positionof the modification (ii).

This embodiment is advantageous in that it contributes to furtherimproving the ability to recruit the effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophagesinvolved, and therefore the elimination of the amyloid deposits.

Other particular embodiments, described hereinafter, make it possible inparticular to further improve the ability to recruit effector cells,more particularly via improved bonding between the Fc region fragmentsconsidered and the Fcgamma R receptors, in particular Fcgamma RIII orCD16, expressed in particular at the surface of polymorphonuclear cellsand macrophages.

Thus, according to another particular embodiment, a fragment of an Fcregion of a human antibody considered in a chimeric protein according tothe invention may exhibit a low degree of fucosylation at the level ofthe oligosaccharide chains borne by Asn297 (Kabat numbering),characterized by a fucose content of less than 65% relative to the totalcontent of the glycan structures at the level of the oligosaccharidechains borne by Asn297.

In another embodiment, a fragment of an Fc region of a human antibodyconsidered in a chimeric protein according to the invention may exhibita low degree of fucosylation, characterized by glycan structures havinga content of less than 50% of G0F+G1F forms described hereinafter,relative to the total content of the glycan structures. For example, afragment of an Fc region of a human antibody considered in a chimericprotein according to the invention may also comprise a content ofgreater than 60% for the G0+G1+G0F+G1F forms, the G0F+G1F forms beingless than 50%.

In another particular embodiment, the antibodies may comprise a contentof greater than 60% for the G0+G1+G0F+G1F forms, the fucose contentbeing less than 65%.

These G0, G0F, G1 and G1F forms are more particularly illustrated inFIG. 8 hereinafter.

According to the final embodiment described above, the fragment of an Fcregion of a human antibody considered in a chimeric protein according tothe invention may also comprise, on an Asn297 glycosylation site, aglycan structure having end mannoses and/or end N-acetylglucosamineswhich are non-intercalated.

The fragment of an Fc region of a human antibody considered in achimeric protein according to the invention may comprise, on the Asn297glycosylation site, a glycan structure of biantennary type, with shortchains, a low degree of sialylation, and a content of greater than 60%for the G0+G1+G0F+G1F forms, the G0F+G1F forms being less than 50%. Forexample, the fragment of an Fc region of a human antibody considered ina chimeric protein according to the invention can have a sialic acidcontent of less than 25%, 20%, 15% or 10%, preferably 5%, 4%, 3% or 2%.

The fragment of an Fc region of a human antibody considered in achimeric protein according to the invention may comprise a content ofgreater than 60%, preferably greater than 80% for the G0+G1+G0F+G1Fforms, it being understood that the G0F+G1F forms are less than 50%,preferably less than 30%.

The fragment of an Fc region of a human antibody considered in achimeric protein according to the invention may comprise glycanstructures of biantennary type, with short chains, a low degree ofsialylation, non-intercalated end attachment point mannoses andN-acetylglucosamines, the glycan structures having a content of greaterthan 60% for the G0+G1+G0F+G1F forms, and a low degree of fucosylation,the glycan structures having a content of less than 50% of G0F+G1Fforms.

Some of the particular embodiments described above are in particulardescribed in greater detail in WO 01/77181 and WO 2012/175874.

As indicated above, a chimeric protein according to the inventioncomprises a hinge region between the human amyloid P component and thefragment of an Fc region of a human antibody to which said human amyloidP component is attached.

This construction has the advantage of ensuring greater accessibilityboth to the human amyloid P component and to the fragment of an Fcregion of a human antibody and also confers greater flexibility on achimeric protein according to the invention. This embodiment isadvantageous in that it therefore contributes to improving the abilityof the human SAP to recognize the amyloid deposits and the ability ofthe Fc region fragments to recruit effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophagesinvolved, and therefore the elimination of the amyloid deposits.

With the proviso of an appropriate architecture, as defined hereinafter,the combining of two fragments of an Fc region of a human antibody asencountered in the immunoglobulins confers, on a chimeric proteinaccording to the invention, an ability to interact with Fc receptorsthat is comparable to that of immunoglobulins. This combining thereforeresults in a functional region capable of recruiting effector cells andof ensuring the elimination of amyloid plaques.

The nature of the hinge region falls within the knowledge of thoseskilled in the art.

More particularly, a hinge region according to the invention may be aspecific peptide sequence comprising at least one cysteine residue orone non-peptide molecule such as polyethylene glycol (PEG).

Preferably, a hinge region in accordance with the invention can bechosen from the hinge regions of human IgG1, human IgG2, human IgG3 orhuman IgG4.

Even more preferentially, a hinge region can comprise at least one aminoacid sequence having at least 60% identity, preferably at least 80%identity, with a sequence chosen from the sequences SEQ ID NOs: 13 and15 to 18, in particular the sequence SEQ ID NO: 13.

A hinge region according to the invention may also be represented byvariants of the sequences SEQ ID NOs: 13 and 15 to 18.

By way of illustration of variants of a hinge region comprising at leastone amino acid sequence having at least 60% identity, preferably atleast 80% identity, with the sequences SEQ ID NOs: 13 and 15 to 18,mention may be made of the sequence SEQ ID NO: 13 in which the firstcysteine is mutated by a serine.

According to one particularly preferred embodiment, a hinge regionaccording to the invention may be represented by the amino acid sequenceSEQ ID NO: 19.

According to one particular embodiment, a hinge region according to theinvention may also include a non-structuring peptide sequence betweenthe hinge region and the amyloid P component.

In particular, such a non-structuring peptide sequence may berepresented by an amino acid sequence SEQ ID NO: 5.

This sequence SEQ ID NO: 5, having the unit (GGGGS)n (or G₄S)n, istherefore more or less long depending on the desired flexibility. Inthis regard, “n” is preferably between 1 and 5, and preferably is equalto 3.

As previously indicated, the ability of a chimeric protein according tothe invention to exhibit a natural affinity of human SAP for amyloiddeposits, but especially to recruit effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophages involvedin the elimination of the amyloid deposits via the fragment of an Fcregion of a human antibody, is conditioned by an appropriatearchitecture, as defined hereinafter.

Thus, according to a first implementation variant, the chimeric proteinaccording to the invention may comprise at least two units, each unitcomprising at least one human amyloid P component and at least onefragment of an Fc region of a human antibody, bonded to each other bymeans of a hinge region, the two units being bonded to each othercovalently by at least one disulfide bridge.

This specific architecture is in particular denoted in the remainder ofthe present application by the expression “dimeric SAP-Fc” and isillustrated in FIG. 1.

This first implementation variant results in the formation of a dimericchimeric protein. This specific architecture is advantageous in that itimproves the ability to recruit effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophagesinvolved, and therefore the elimination of the amyloid deposits.

For each unit, said human amyloid P component and said fragment of an Fcregion of a human antibody are bonded to each other by a hinge region,as previously defined.

According to this implementation variant, the fragments of an Fc regionof a human antibody of the various units considered may be identical ordifferent.

Alternatively, a dimeric SAP-Fc chimeric protein according to theinvention may comprise at least two units, each unit comprising at leastone human amyloid P component and at least one fragment of an Fc regionof a human antibody, bonded to each other by means of a hinge region,but the two units being bonded to each other by a bond formed from atleast two poly(ethylene glycol) (PEG) groups.

Since a chimeric protein of dimeric SAP-Fc type results from the bondingof two units as defined above, each unit being bonded to each other byat least one disulfide bridge or by a bond formed from at least two PEGgroups, the present invention also relates to a chimeric proteinrepresented by a single unit by way of intermediate compound.

Thus, the present invention also relates, by way of intermediatecompound, to a chimeric protein comprising a single human amyloid Pcomponent and a single fragment of an Fc region of a human antibody, thehuman amyloid P component and the fragment of an Fc region being bondedto each other by means of a hinge region.

Such an intermediate compound may also be denoted in the remainder ofthe present description by the expression “monomeric SAP-Fc”.

Such an intermediate compound can be represented by an amino acidsequence having at least 80%, preferably at least 90%, identity with thesequence SEQ ID NO: 7.

A protocol for preparing a dimeric SAP-Fc chimeric protein as previouslydefined starting from a “monomeric SAP-Fc” intermediate chimeric proteinfalls within the general knowledge of those skilled in the art.

Such an aspect is in particular subsequently described in the examples.

According to another implementation variant, the chimeric proteinaccording to the invention may comprise at least one human amyloid Pcomponent and at least two fragments of an Fc region of a human antibody(i.e. first and second fragments of an Fc region of a human antibody),which may be identical or different, said human amyloid P component andsaid first fragment of an Fc region of a human antibody being bonded toeach other by means of a hinge region, the first and second fragments ofan Fc region being bonded to each other covalently by means of a bondformed from a spacer chain and a hinge region identical to or differentthan that previously mentioned, and form a single polypeptide chainconstituting a functional dimeric Fc region.

This specific architecture is in particular denoted in the remainder ofthe present application by the expression “monomeric SAP-ScFc” and isillustrated in FIG. 2.

In other words, a monomeric SAP-ScFc protein according to the inventioncomprises, from the N-terminal part to the C-terminal part, (1) a humanamyloid P compound, (2) a hinge region, (3) a first fragment of an Fcregion of a human antibody, (4) a spacer chain, (5) a hinge region,identical to or different than that considered in (2) above, and (6) asecond fragment of an Fc region of a human antibody, identical to ordifferent than that considered in (3) above.

Proteins which have this particular architecture, which can be called“single chain Fc” or “ScFc”, comprising at least two fragments of an Fcregion of a human antibody, which are identical or different, and beingbonded to each other covalently so as to form a single polypeptide chainconstituting a functional dimeric Fc region, are in particular describedin WO 2008/143954.

In this regard, the spacer chain considered in the bonding between thefirst and second fragments of an Fc region can preferably be representedby an amino acid sequence SEQ ID NO: 5.

In this respect, this sequence SEQ ID NO: 5, having the unit (GGGGS)n(or G₄S)n, is therefore more or less long depending on the desiredflexibility. In this regard, “n” is preferably between 1 and 5, andpreferably equal to 3.

Moreover, the human amyloid P component and the first fragment of an Fcregion of a human antibody to which said human amyloid P component isattached are separated from each other by means of a hinge region aspreviously defined.

According to yet another implementation variant, a chimeric proteinaccording to the invention can result from the natural pairing of twomonomeric SAP-ScFc chimeric proteins, bonded to each other by means ofat least two disulfide bridges or of at least two bonds, a bond beingformed from at least two poly(ethylene glycol) (PEG) groups.

This specific architecture is in particular denoted in the remainder ofthe present application by the expression “dimeric SAP-ScFc” and isillustrated in FIG. 3.

These three implementation variants dimeric SAP-Fc, monomeric SAP-ScFcand dimeric SAP-ScFc of a chimeric protein according to the inventionall comprise at least two Fc region fragments, which therefore resultsin a functional region responsible for the ability of these particulararchitectures to recruit effector cells and thus to ensure theelimination of the amyloid plaques.

Moreover, the monomeric SAP-Fc and monomeric SAP-ScFc chimeric proteinsaccording to the invention and as previously described can pair togetherto form a pentameric structure, or else a decameric structure (i.e.resulting from two pentameric structures interacting face-to-face).Indeed, it has been shown that the serum SAP protein can combine withitself to form pentameric and dimeric structures (Hutchinson et al.,2000, Molecular Medicine, 6:482).

According to another of its aspects, the present invention relates to anucleic acid comprising at least one polynucleotide sequence encoding atleast one chimeric protein according to the invention.

Since the formation of the dimeric SAP-Fc and dimeric SAP-ScFcstructures results from a natural pairing phenomenon, the polynucleotidesequence preferably encodes at least the monomeric SAP-Fc or monomericSAP-ScFc chimeric protein.

According to yet another of its aspects, the present invention relatesto a vector into which a nucleic acid as defined above is inserted.

According to another of its aspects, the present invention relates to ahost cell transfected with a vector as previously defined.

According to yet another of its aspects, the present invention relatesto a process for producing a chimeric protein as previously defined,said process comprising at least the steps consisting in:

a) transfecting a host cell with a vector as defined above;

b) culturing said host cell under conditions such that the chimericprotein is produced; and

c) collecting said chimeric protein produced by said host cell at theend of step b).

Considering the dimeric SAP-Fc chimeric protein, it should be noted thatthe step consisting in covalently bonding, by means of at least onedisulfide bridge, the two units each comprising at least one humanamyloid P component and at least one fragment of an Fc region of a humanantibody with, for each unit, said human amyloid P component beingbonded to said fragment of an Fc region to which it is attached by meansof a hinge region, is a step which occurs naturally in the host cell.

In the same way, the pairing of two monomeric SAP-ScFc proteins forobtaining the dimeric SAP-ScFc chimeric protein takes place naturally inthe host cell, by the formation of at least two disulfide bridges.

According to yet another of its aspects, the present invention relatesto a pharmaceutical composition comprising a chimeric protein accordingto the invention and a pharmaceutically acceptable excipient.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof as a medicament.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof for eliminatingthe amyloidosis deposits in the organs.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for inducing an activation ofthe phagocytosis of the ligand recognized by the human amyloid Pcomponent by the neutrophil polymorphonuclear cells and/or themonocyte-macrophages.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof for treatingamyloidosis, in particular amyloidosis of AL type.

According to yet another of its aspects, the present invention relatesto a process for treating amyloidosis, in particular amyloidosis of ALtype, comprising at least one step of administering, to an individual inneed thereof, an effective amount of at least one first active agentrepresented by a chimeric protein or a composition as previouslydefined.

According to one particular embodiment, said process may also comprise astep of administering, prior to, concomitant with and/or subsequent tothe step of administering the first active agent, at least one secondactive agent distinct from said first active agent, the second activeagent preferably being chosen from the group comprising4-[bis(chloroethyl)amino] phenylalanine (melphalan);9-fluoro-11β,17,21-trihydroxy-16a-methylpregna-1,4-diene-3,20-dione(dexamethasone); prednisone; dimethyl sulfoxide (DMSO);N-[(7S)-5,6,7,9-tetrahydro-1,2,3,10-tetramethoxy-9-oxobenzo[a]heptalen-7-yl)acetamide](colchicine);(7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione(doxorubicin); active agents capable of reacting with the amyloid Pcomponent, in particular of bis-d-proline type, and more particularlythe compound(R)-1-[6-[(R)-2-carboxypyrrolidin-1-yl]-6-oxohexanoyl]pyrrolidine-2-carboxylicacid); proteasome inhibitors, for example bortezomib, carfilzomib,marizomib, ixazomib, delanzomib, ONX-912 or revlimid; and a mixturethereof.

According to yet another of its aspects, the present invention relatesto the use of at least one chimeric protein as defined above, as a toolfor in vitro or ex vivo characterization of the presence of anamyloidosis deposit.

According to yet another of its aspects, the present invention relatesto the use of at least one chimeric protein as defined above, as a toolfor in vitro or ex vivo characterization of the presence of anamyloidosis deposit.

According to a first implementation variant, the chimeric protein isradiolabeled; preferably, the human amyloid P component is representedby ¹²³I-SAP.

According to a second implementation variant, the chimeric protein isidentified by means of a radiolabeled anti-Fc antibody; for example,said anti-Fc antibody is coupled to peroxidase.

A chimeric protein according to the invention may also be identified bymeans of any technique known to those skilled in the art. In thisrespect, mention may in particular be made of the technique via couplingwith fluorophores and microbeads, as described in Neri et al. (1997) NatBiotech, or else the techniques described in Brack et al. (2005) EJNM,Santimaria (2003) Clinical cancer res, Borsi et al. (2002) Int J cancer,Berndorff (2006) J Nucl Med and Joseph et al. (2004) Pharm Res.

DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a chimeric protein according to the inventioncomprising two units each comprising a human amyloid P component and afragment of an Fc region of a human antibody, bonded to each other by ahinge region, the two units being bonded to each other covalently by adisulfide bridge (=dimeric SAP-Fc chimeric protein).

FIG. 2 illustrates a chimeric protein according to the inventioncomprising a human amyloid P component and two fragments of an Fc regionof a human antibody (i.e. first and second fragments of an Fc region ofa human antibody), the human amyloid P component being attached to thefirst fragment of an Fc region by a hinge region and the two fragmentsof an Fc region, which are identical or different, being bonded to eachother covalently by a bond formed from a spacer chain and a hinge regionand form a single polypeptide chain constituting a functional dimeric Fcregion (=monomeric SAP-ScFc chimeric protein).

FIG. 3 illustrates a chimeric protein according to the inventionresulting from the pairing of two monomeric SAP-ScFc chimeric proteinsbonded to each other by two disulfide bridges (=dimeric SAP-ScFcchimeric protein).

FIG. 4 illustrates the commercial cloning vector pGEM®-T Easy (Promega).

FIG. 5 illustrates the commercial expression vector pCpG (invivogen).

FIG. 6 illustrates the results of the purification step on protein Aaccording to the invention considered in example 3 hereinafter, for thedimeric SAP-Fc (FIG. 6A) and monomeric SAP-ScFc (FIG. 6B) chimericproteins (x-axis: volume injected in ml; y-axis: measurement of opticaldensity at 280 nm in arbitrary units). In FIGS. 6A and 6B, the peakslocated between 0 and 60 ml correspond to the exclusion volume. In FIGS.6A and 6B, the peaks located between 60 and 70 ml correspond to thechimeric proteins according to the invention.

FIG. 7 illustrates the results of the purification step by Westernblotting considered in example 3 hereinafter, for the SAP-Fc andSAP-ScFc chimeric proteins. Sample 1: characterizes the SAP-Fc: sample2: characterizes the SAP-ScFc. The band at 75 kDa corresponds to themonomeric SAP-ScFc architecture. The band at 100 kDa corresponds to thedimeric SAP-Fc architecture.

FIG. 8 illustrates the glycan structures that can be considered in thecontext of the fucosylation of an Fc region of a human antibody.

FIG. 9 illustrates the protocol for inducing AA amyloidosis in Balb/cand VH-LMP2A mice. In this FIG. 9, AEF IV=“Amyloid Enhancing Factor”given Intravenously; SC=“Subcutaneous”; IgIR=“Immunoglobulin Irrelevantanti-FVIII” (human IgG1).

FIG. 10 illustrates the effect of various compounds, including theSAP-Fc and SAP-ScFc chimeric proteins according to the invention, on theamyloidosis deposits induced in Balb/c mice treated according to theprotocol detailed in FIG. 9. FIG. 10 illustrates more particularly theamount of amyloidosis deposits observed in Balb/c mice having receivedinjections of PBS, of IgIR irrelevant IgG1 proteins (control) or ofSAP-Fc or SAP-ScFc chimeric proteins according to the invention. Theseresults are obtained from the spleens of said mice.

FIG. 11 illustrates the effect of various compounds, including theSAP-ScFc chimeric proteins according to the invention, on theamyloidosis deposits induced in VH-LMP2A mice treated according to theprotocol detailed in FIG. 9. FIG. 11 illustrates more particularly theamount of amyloidosis deposits observed in VH-LMP2A mice having receivedinjections of PBS, of SAP proteins as such (i.e. devoid of the fragmentof an Fc region of a human antibody) and of SAP-ScFc chimeric proteinsaccording to the invention. These results are obtained from the spleensof said mice.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above and illustrated in the examples hereinafter, theinventors have shown that a chimeric protein, by taking advantage of, onthe one hand, the natural affinity of SAP for amyloid deposits and, onthe other hand, the ability of the Fc region of antibodies to recruiteffector cells, in particular neutrophil polymorphonuclear cells andmonocyte-macrophages, is particularly advantageous in terms ofeliminating the amyloid deposits, this being whatever the type ofamyloidosis considered.

DEFINITIONS

Preliminarily, in order for it to be possible to understand theapplication more clearly, several definitions are stated below. Thesedefinitions are supposed to encompass the grammatical equivalents.

For the purposes of the present invention, the term “chimeric protein”is intended to denote a protein consisting of a first amino acidsequence derived from a first source, covalently bonded to a secondamino acid sequence derived from a second source, in which the first andsecond source are not identical or, in other words, characterize twodifferent biological entities. In the case in point, one among the firstor second amino acid sequence represents at least one human amyloid Pcomponent and the other represents at least one fragment of an Fc regionof a human antibody. In the context of the present invention, the firstand second amino acid sequences are bonded to each other by means of ahinge region, in particular as previously defined.

In the context of the present invention, a chimeric protein is alsointended to denote dimeric forms of a protein as defined above, or of aderivative thereof.

The term “polynucleotide” is intended to mean, according to theinvention, a compound comprising a nucleotide polymer, which encompassesa ribonucleotide (RNA) polymer and a deoxyribonucleotide (DNA) polymer,said nucleotides being optionally chemically modified. According to theinvention, a polynucleotide can advantageously have a length rangingfrom 5 to 3000 nucleotides. A polynucleotide conventionally encompassespolyribonucleotides and the polydeoxyribonucleotides, where appropriatechemically modified. In certain embodiments, a polynucleotide consistsof a polymer of nucleotides, ribonucleotides or deoxyribonucleotides. Inother embodiments, a nucleic acid consists essentially of a nucleotidepolymer and comprises a non-nucleotide part, said non-nucleotide partpreferentially being of reduced length, compared with the length of thenucleotide part, for example a linear length less than the lengthoccupied by a chain of five nucleotides, ribonucleotides ordeoxyribonucleotides. Preferentially, the non-nucleotide part is notpolypeptide in nature, or alternatively does not contain an amino acidresidue. A polynucleotide can comprise one or more modified nucleotides,such as methylated nucleotides, it being possible for the modificationsto be carried out before, during or after assembly of the nucleotidepolymer. In certain embodiments, the non-nucleotide part can consist ofa spacer chain comprising a free carboxyl group or of a spacer chaincomprising a free amine group.

For the purposes of the present description, the terms “polynucleotideentity” and “polynucleotide” are used without implied distinction todenote the same subject.

According to the invention, the term “polypeptide” is intended to mean achain of at least two amino acid residues, which encompasses a changeranging from 2 to 1000 amino acid residues in length, said amino acidresidues being bonded to each other by covalent bonds, including bypeptide bonds. In the present description, the term “polypeptide” can beused to denote without implied distinction a protein, a peptide or anoligopeptide. The term “polypeptide” encompasses polypeptides chemicallymodified by one or more functional groups or by one or more non-peptidemolecules, with the exception of a modification by a polynucleotide.

For the purposes of the present description, the terms “polypeptideentity” and “polypeptide” are used without implied distinction to denotethe same subject.

The term “amino acid” encompasses any one of the 22 natural amino acidresidues, and the non-natural analogs thereof. The amino acids encompassthe residues alanine (Ala; A), arginine (Arg; R), asparagine (Asp; N),aspartic acid (Asp; D), cysteine (Cys; C), glutamic acid (Glu; E),glutamine (Gln; Q), glycine (Gly; G), histidine (His; H), isoleucine(Ile; I), leucine (Leu; L), lysine (Lys; K), methionine (Met; M),phenylalanine (Phe; F), proline (Pro; P), serine (Ser; S), threonine(Thr; T), tryptophan (Trp; W), tyrosine (Tyr; Y), valine (Val; V),pyrrolysine and selenocysteine. The amino acids encompass the L-aminoacids and the D-amino acids. Preferentially, the amino acids are theL-amino acids.

For the purposes of the present invention, the term “amyloid Pcomponent” or “SAP protein” is intended to denote a glycoprotein,belonging to the family of pentraxin proteins, which has acharacteristic pentameric organization. It is a glycoproteinconstituting all the amyloid deposits, in particular those isolated fromthe pancreas of long-term diabetics. It is made up of 10 identicalglycosylated polypeptide subunits, noncovalently linked to form twopentamers arranged in two helical filaments. Each subunit of thepentagonal structure obtained has a molecular weight of 23 to 25 000Daltons. SAP is part of the family of pentraxins such as CRP (c-reactiveprotein) with which it exhibits a structural homology, the N-terminalparts being homologous. SAP is naturally present in the blood in anamount of approximately 20 to 30 mg/l of blood (Pepys, M. B., et al.,Ann Rev Med, 2006; 57:223-41.)

The term “Fc” or “Fc region”, as used here, is intended to mean thecrystallizable fragment generated during the enzymatic digestion ofimmunoglobulins by papain. The Fc fragment refers to the last twoconstant regions of IgA, IgD and IgG immunoglobulins, and to the lastthree constant regions of IgE and IgM. For IgA and IgM, Fc may comprisethe J chain. For IgG, Fc comprises the Cgamma2 and Cgamma3immunoglobulin domains (Cγ2 and Cγ3 which are the CH2 and CH3 domains,respectively). The heavy chain of the Fc region of human IgG1 is definedhere as comprising C226 residues at its carboxyl end, where thenumbering of the amino acids of the Fc region is that of the EU indexproposed by Kabat. In the context of human IgG1, the CH2 domain refersto positions 237 to 340 and the CH3 domain refers to positions 341 to447 according to the EU index proposed by Kabat.

The term “antibody” is used here in the broadest sense. The term“antibody” is therefore intended to denote any polypeptide whichcomprises at least: (i) one Fc region and (ii) one polypeptide bindingdomain derived from a variable region of an immunoglobulin. Saidpolypeptide binding domain is capable of binding specifically to a giventarget antigen or a group of target antigens. A polypeptide bindingdomain which derives from a variable region of an immunoglobulincomprises one or more CDRs (“complementarity determining regions”). Theantibodies comprise, but are not limited to, full-lengthimmunoglobulins, monoclonal antibodies, multispecific antibodies, Fcfusion proteins comprising at least one variable region, syntheticantibodies (sometimes referred to as “mimetic antibodies”), chimericantibodies, humanized antibodies, whole human antibodies, fusionprotein-antibodies, antibody conjugates, and respective fragmentsthereof.

The term “full-length antibody” or “immunoglobulin” as used here isintended to mean the structure which constitutes the natural biologicalform of an antibody, comprising the variable and constant regions. The“full-length antibodies” cover monoclonal full-length antibodies,wild-type full-length antibodies, chimeric full-length antibodies,humanized full-length antibodies, the list not being limiting.

In most mammals, including humans and mice, the structure of full-lengthantibodies is generally a tetramer. Said tetramer is composed of twoidentical pairs of polypeptide chains, each pair having a “heavy” chain(typically having a molecular weight of approximately 50-70 kDa) and a“light” chain (typically having a molecular weight of approximately 25kDa). In some mammals, for example in camels and lamas, the full-lengthantibodies may consist of only two heavy chains, each heavy chaincomprising a variable domain attached to the Fc region.

The amino-terminal part of each chain comprises a variable region ofapproximately 100 to 110 amino acids which is responsible for antigenrecognition. In the variable region, three loops are assembled for eachof the V domains of the heavy chain and of the light chain so as to forman antigen-binding site. Each of these loops relates to a CDR, in whichthe variation of the amino acid sequence is greatest.

The carboxy-terminal part of each chain defines a constant regionprincipally responsible for the effector function. Kabat et al. hascollected numerous variable-region primary sequences of heavy chains andof light chains. On the basis of the degree of sequence conservation,they have classified the individual primary sequences into the CDRs andhave made a list thereof (see Sequences of Immunological Interest, 5thedition, NIH Publication, No. 91-3242, E A Kabat et al., incorporatedherein by way of reference in its entirety).

In the case of human immunoglobulins, the light chains are classified askappa and lambda light chains. The heavy chains are classified as mu,delta, gamma, alpha, or epsilon, and define the isotype of the antibody,such as IgM, IgD, IgG, IgA and IgE, respectively. IgG has severalsubclasses, including, but without being limited thereto, IgG1, IgG2,IgG3 and IgG4. IgM has several subclasses, including, but without beinglimited thereto, IgM1 and IgM2. Thus, the term “isotype” as used hereinis intended to mean one of the immunoglobulin subclasses defined by thechemical and antigenic characteristics and the characteristics of theirconstant regions. The known human immunoglobulin isotypes are IgG1,IgG2, IgG3, IgG4, IgA1, IgA2, IgM1, IgM2, IgD and IgE.

The term “IgG” as used herein is intended to mean a polypeptidebelonging to the antibody class which is substantially encoded by arecognized immunoglobulin gamma gene. In humans, IgG comprises thesubclasses or isotypes IgG1, IgG2, IgG3 and IgG4.

The full-length IgGs are tetramers and are composed of two identicalpairs of two immunoglobulin chains, each pair having a light chain and aheavy chain, each light chain comprising the VL and CL domains, and eachheavy chain comprising the VH, Cγ1 (also called CH1), Cγ2 (also calledCH2) and Cγ3 (also called CH3) domains. In the context of human IgG1,“CH1” refers to positions 118 to 220, the CH2 domain refers to positions237 to 340 and the CH3 domain refers to positions 341 to 447 accordingto the EU index proposed by Kabat. The IgG heavy chain also comprises ahinge region (“hinge domain”) which refers to positions 221 to 236 inthe case of IgG1.

For the purposes of the present invention, the term “fragments” of an Fcregion is intended to denote identical or different polypeptides whichcomprise one or more polypeptides derived from a wild-type Fc region,preferably from the CH2-CH3 domain which is under the hinge region of awild-type IgG. The fragments of an Fc region according to the inventionare such that, when they are in dimeric form such as those previouslydescribed (i.e. within the dimeric SAP-Fc, monomeric SAP-ScFc anddimeric SAP-ScFc chimeric proteins), they retain their ability torecruit effector cells, in particular neutrophil polymorphonuclear cellsand monocyte-macrophages. To this effect, the fragments of an Fc regionaccording to the invention have a dissociation constant for FcRn of lessthan 1 microM according to SPR assay.

For the purposes of the present invention, the term “FcRn” or “neonatalFc receptor” is intended to denote a protein which binds to the Fcregion of IgG antibodies and is at least partly encoded by an FCRN gene.The FcRn may be from any organism, including, but not limited to,humans, mice, rats, rabbits and monkeys. In the light of the therapeuticindications considered in the present application, the FcRn is humanFcRn. As is known in the art, the functional FcRn protein comprises twopolypeptides, often denoted as the heavy chain and the light chain. Thelight chain is beta-2-microglobulin and the heavy chain is encoded bythe RRFC gene. Unless otherwise indicated, FcRn or the FcRn proteinrefers to the complex of the α-chain with beta-2-microglobulin. Inhumans, the gene encoding FcRn is called FCGRT.

As indicated above, according to one particular embodiment, the Fcregion or the fragment of an Fc region of a human antibody of a chimericprotein according to the invention may exhibit an improved affinity forFcRn compared with the Fc region of a fragment of an Fc region of aparent human antibody.

The term “parent” as used herein is intended to mean a nonmodifiedpolypeptide which is subsequently modified to produce a variant. Saidparent polypeptide may be a naturally existing polypeptide, a variant ofa natural polypeptide, the engineered version or a syntheticpolypeptide. The parent polypeptide may refer to the polypeptide itself,or to the amino acid sequence which encodes it. In the context of thepresent invention, the parent polypeptide is a human antibody whichcomprises an Fc region. The parent polypeptide may optionally comprisepreexisting amino acid modifications in its Fc region (for example an Fcmutant) compared with wild-type Fc regions.

The term “improved affinity for FcRn” as used herein is intended to meanan increase in the binding affinity, in vivo or in vitro, of a fragmentof an Fc region for FcRn compared with a fragment of an Fc regionderived from a parent human antibody.

The affinity for FcRn, of a fragment of an Fc region of a human antibodyaccording to the invention, can be evaluated by well-known prior artmethods. For example, those skilled in the art can determine thedissociation constant (Kd) using surface plasmon resonance (SPR), asdescribed for example in Yeung Y A, et al. (2009, J. Immunol, vol. 182:7663-7671). In the case of a fragment of an Fc region of a humanantibody according to the invention comprising certain modifications inits amino acid sequence compared with a fragment of an Fc region of aparent human antibody, for the purposes of improving its affinity forFcRn, the presence of a Kd value 1.5 to 3 times lower (higher affinity)than that of the fragment of an Fc region of a parent human antibodyconfirms this improvement.

As an alternative technique, those skilled in the art can perform anappropriate ELISA assay, as described for example by Deng et al. (2012,Landes Bioscience, vol. 4(1): 101-109). An appropriate ELISA assay makesit possible to compare the strength of binding between a fragment of anFc region of a human antibody according to the invention comprisingcertain modifications and a fragment of an Fc region of a parent humanantibody. A fragment of an Fc region of a human antibody according tothe invention comprising certain modifications thus exhibits an improvedaffinity for FcRn if its specific signal is at least 1.2 times stronger,preferably at least 4 times stronger, than that measured with a fragmentof an Fc region of a parent human antibody.

For the purposes of improving the affinity for FcRn, the Fc region ofthe antibody of the chimeric protein according to the invention cancomprise certain modifications in its amino acid sequence.

For the purposes of the present invention, the term “modifications inthe amino acid sequence” is intended to denote a change in the aminoacid sequence of a polypeptide. A modification in the amino acidsequence, or changing of amino acids, comprises a substitution, aninsertion and/or a deletion of an amino acid included in a polypeptidesequence.

The term “substitution of an amino acid” or “substitution” is intendedto mean herein the replacement of an amino acid in a particular positionin a parent polypeptide sequence with another amino acid. For example,the substitution N434S refers to a polypeptide in which the asparaginein position 434 is replaced with serine.

The term “insertion of an amino acid” or “insertion” is intended to meanherein the addition of an amino acid at a particular position in aparent polypeptide sequence. For example, insert G>235-236 denotes aninsertion of glycine between positions 235 and 236.

The term “deletion of an amino acid” or “deletion”, as used herein, isintended to mean the deletion of an amino acid at a particular positionin a parent polypeptide sequence. For example, E294del denotes thedeletion of glutamic acid in position 294.

For example, the following modification form is preferentially used:434S, or N434S, means that the parent amino acid in position 434, i.e.asparagine, is replaced with serine. In the case of a combination ofsubstitutions, the preferred format is the following: 259I/315D/434Y orV259I/N315D/N434Y. This means that there are three substitutions, one inposition 259, one in position 315 and one in position 434, and that theamino acid in position 259 of the parent polypeptide, i.e. the valine,is replaced with isoleucine, that the amino acid in position 315 of theparent polypeptide, i.e. the asparagine, is replaced with aspartic acidand that the amino acid in position 434 of the parent polypeptide, i.e.the asparagine, is replaced with tyrosine.

Chimeric Protein According to the Invention

As previously indicated, according to a first of its aspects, thepresent invention relates to a chimeric protein comprising at least onehuman amyloid P component and at least one fragment of an Fc region of ahuman antibody, the human amyloid P component and the fragment of an Fcregion to which it is attached being bonded to each other by means of ahinge region.

According to one particular embodiment, the human amyloid P componentpresent in a chimeric protein according to the invention can berepresented by an amino acid sequence having at least 80% identity withthe sequence SEQ ID NO: 1, preferably at least 90% identity with thesequence SEQ ID NO: 1.

For the purposes of the present invention, an amino acid sequence havingat least 80% identity with a reference sequence has an identity of atleast 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% with said reference sequence.

For determining the percentage identity of two amino acid sequences,sequence alignment methods are well known to those skilled in the art.The sequences are aligned for the purposes of optical comparison. Forexample, gaps can be introduced into one of or both the first and secondamino acid or nucleotide sequences for optimal alignment and thenon-homologous sequences can be discarded for the purposes ofcomparison. By way of example and without being limiting, the percentageidentity of two amino acid or nucleotide sequences can be carried outwith CLUSTAL W (version 1.82, version 2), CLUSTAL OMEGA, BLAST orMULTALIN.

According to another particular embodiment, the human amyloid Pcomponent present in a chimeric protein according to the invention canbe represented by an amino acid sequence encoded by a nucleic acidsequence having at least 80% identity with the sequence SEQ ID NO: 2,preferably at least 90% identity with the sequence SEQ ID NO: 2.

Thus, for the purposes of the present invention, a nucleic acid sequencehaving at least 80% identity with a reference sequence has an identityof at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%,92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% with said referencesequence.

According to another particular embodiment, the Fc region responsiblefor each of the fragments of an Fc region of a human antibody of thechimeric protein according to the invention may be an Fc region of ahuman immunoglobulin, preferably an Fc region of an IgG, better still anFc region of an IgG1 or of an IgG2, and more particularly an Fc regionof an IgG1.

According to another particular embodiment, the fragment of an Fc regionof a human antibody of a chimeric protein according to the invention canbe represented by at least one amino acid sequence having at least 80%identity with the sequence SEQ ID NO: 3.

According to yet another particular embodiment, the fragment of an Fcregion of a human antibody of a chimeric protein according to theinvention can be represented by at least one amino acid sequence encodedby a nucleic acid sequence having at least 80% identity with thesequence SEQ ID NO: 4.

According to one particular embodiment, the fragment of an Fc region ofa human antibody of a chimeric protein according to the invention canexhibit an improved affinity for FcRn, compared to a fragment of an Fcregion of a parent human antibody.

In this respect, the Fc region of the antibody of the chimeric proteinaccording to the invention can comprise at least two modifications inthe amino acid sequence, namely:

(i) a modification in the amino acid sequence chosen from the groupconsisting of 378V, 378T, 434Y and 434S, and

(ii) at least one modification in the amino acid sequence chosen fromthe group consisting of 226G, 230S, 230T, 230L, 241 L, 264E, 307P, 315D,330V, 362R, 378V, 378T, 389T, 389K, 434Y and 434S,

it being understood that the numbering of the amino acids of the Fcregion is that of the EU index proposed by Kabat and on the conditionthat the modification (i) does not occur at the same amino acid positionas the modification (ii).

This embodiment is advantageous in that the combination of variousmutations contributes to also improving the ability to recruit effectorcells, in particular the neutrophil polymorphonuclear cells and themonocyte-macrophages involved, and therefore the elimination of theamyloid deposits.

As previously denoted, a human amyloid P component is attached to thefragment of an Fc region of a human antibody by means of a hinge region.

This construction has the advantage of ensuring greater accessibilityboth to the amyloid P component and to the fragment of an Fc region ofan antibody and also confers greater flexibility on a chimeric proteinaccording to the invention. This embodiment is advantageous in that itcontributes to improving the ability of the SAP to recognize the amyloiddeposits and the recruitment of effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophagesinvolved, and therefore the elimination of the amyloid deposits.

The nature of the hinge region can be chosen according to the knowledgeof those skilled in the art. Preferably, the hinge region is a specificpeptide sequence comprising at least one cysteine residue or onenon-peptide molecule such as polyethylene glycol (PEG).

Preferably, a hinge region in accordance with the invention can bechosen from the hinge regions of human IgG1, human IgG2, human IgG3 orhuman IgG4.

Advantageously, a hinge region according to the invention is that ofhuman IgG1.

In this regard, a hinge region according to the invention may compriseat least one amino acid sequence having at least 60% identity,preferably at least 80% identity, with a sequence chosen from thesequences SEQ ID NOs: 13 and 15 to 18, preferably with the sequence SEQID NO: 13.

A hinge region in accordance with the invention can, for example, berepresented by the sequence SEQ ID NO: 19.

According to one particular embodiment, a non-structuring peptidesequence can also be present between the hinge region and the amyloid Pcomponent.

In particular, such a non-structuring peptide sequence can berepresented by the sequence SEQ ID NO: 5.

This sequence, having the (G₄S)n unit, is therefore more or less longdepending on the desired flexibility. In this regard, “n” is preferablybetween 1 and 5.

According to a first implementation variant, the chimeric proteinaccording to the invention may comprise at least two units, each unitcomprising at least one human amyloid P component and at least onefragment of an Fc region of a human antibody, bonded to each other bymeans of a hinge region, the two units being bonded to each othercovalently by at least one disulfide bridge.

This first implementation variant, characterizing the dimeric SAP-Fcarchitecture, is in particular illustrated in FIG. 1 hereinafter.

This first implementation variant results in the formation of a dimericchimeric protein. This specific architecture is advantageous in that itresults in effective recruitment of effector cells, in particular theneutrophil polymorphonuclear cells and the monocyte-macrophagesinvolved. As a result, this dimeric chimeric protein could beparticularly effective in eliminating amyloid deposits.

In the light of the aforementioned, a chimeric protein according to thisfirst implementation variant can therefore comprise at least two aminoacid sequences, it being possible for each sequence, which may beidentical or different, to be represented by an amino acid sequencehaving at least 80% identity, preferably at least 90%, with the sequenceSEQ ID NO: 7, each of the sequences being bonded to each othercovalently by at least one disulfide bridge.

According to a second implementation variant, the chimeric proteinaccording to the invention may comprise at least one human amyloid Pcomponent and at least two fragments of an Fc region of a human antibody(i.e. first and second fragments of an Fc region of a human antibody),with a hinge region between said human amyloid P component and the firstfragment of an Fc region of a human antibody to which it is attached,the two fragments of an Fc region, which may be identical or different,being bonded to each other covalently by means of a bond formed from aspacer chain and a hinge region, identical to or different than thatmentioned above, and form a single polypeptide chain constituting afunctional dimeric Fc region.

This second implementation variant, characterizing the monomericSAP-ScFc architecture, is in particular illustrated in FIG. 2hereinafter.

In this regard, the fragments of an Fc region may preferably be bondedto each other by means of a spacer chain represented by at least oneamino acid sequence represented by the sequence SEQ ID NO: 5.

This sequence SEQ ID NO: 5, having the unit (GGGGS)n or (G₄S)n, istherefore more or less long depending on the desired flexibility. Inthis regard, “n” is preferably between 1 and 5, and preferably equal to3.

In other words, a monomeric SAP-ScFc protein comprises, from theN-terminal part to the C-terminal part, (1) a human amyloid P compound,(2) a hinge region, (3) a first fragment of an Fc region of a humanantibody, (4) a spacer chain, (5) a hinge region, identical to ordifferent than that considered in (2) above, and (6) a second fragmentof an Fc region of a human antibody, identical to or different than thatconsidered in (3) above.

According to this second implementation variant, the architecture, fromthe N-terminal part to the C-terminal part, comprising (i) a hingeregion, (ii) a first fragment of an Fc region of a human antibody, (iii)a spacer chain, (iv) a hinge region, identical to or different than thatconsidered in (i) above, and (v) a second fragment of an Fc region of ahuman antibody, identical to or different than that considered in (ii)above, can be represented by at least one amino acid sequence having atleast 80% identity with the sequence SEQ ID NO: 11.

In this regard, the architecture, from the N-terminal part to theC-terminal part, comprising (i) a hinge region, (ii) a first fragment ofan Fc region of a human antibody, (iii) a spacer chain, (iv) a hingeregion, identical to or different than that considered in (i) above, and(v) a second fragment of an Fc region of a human antibody, identical toor different than that considered in (ii) above, can be represented byan amino acid sequence encoded by a nucleic acid sequence having atleast 80% identity with the sequence SEQ ID NO: 12.

In the light of the aforementioned, a chimeric protein according to thissecond implementation variant may comprise at least one amino acidsequence having at least 80% identity with the sequence SEQ ID NO: 9.

A chimeric protein according to this second implementation variant mayalso comprise at least one amino acid sequence encoded by a nucleic acidsequence having at least 80% identity with the sequence SEQ ID NO: 10.

According to a third implementation variant, the chimeric proteinaccording to the invention may result from the natural pairing of twomonomeric SAP-ScFc proteins, bonded to each other by means of at leasttwo disulfide bridges or of at least two bonds, one bond being formedfrom at least two poly(ethylene glycol) (PEG) groups.

This third implementation variant, characterizing the dimeric SAP-ScFcarchitecture, is in particular illustrated in FIG. 3 hereinafter.

Considering the dimeric SAP-Fc and dimeric SAP-ScFc chimeric proteins,the covalent bond(s) between each monomeric SAP-Fc or monomeric SAP-ScFcunit is (are) preferably located at the level of the cysteine residuesof the hinge regions.

Vector Nucleic Acids and Host Cells According to the Invention

According to another of its aspects, the present invention relates to anucleic acid comprising at least one polynucleotide sequence encoding atleast one chimeric protein according to the invention.

Since the formation of the dimeric SAP-Fc and dimeric SAP-ScFcstructures results from a natural pairing phenomenon, the polynucleotidesequence preferably encodes at least the monomeric SAP-Fc or monomericSAP-ScFc chimeric protein.

According to yet another of its aspects, the present invention relatesto a vector, preferably an expression vector, into which a nucleic acidas defined above is inserted.

Preferably, a particularly suitable vector is the pCpG vector (Cayla,Invivogen) which allows very good results regarding the production of Iglight chains in SP2/0 and CHO.

According to another of its aspects, the present invention relates to ahost cell transfected with a vector as previously defined, in particulara bacterial, yeast or fungal cell or a mammalian cell, or else a cellfrom transgenic animals.

Preferably, by way of particularly suitable host cell, mention may bemade of eukaryotic cells, more particularly cells chosen from the groupconsisting of the following cells: YB2/0, in particular the linedeposited with the “American Type Culture Collection” under ATCC No.CRL-1662), SP2/0, YE2/0, 1R983F, Namalwa, PER.C6, the CHO cell lines, inparticular CHO-K-1, CHO-Lecl0, CHO-Lecl, CHO-Lecl3, CHO Pro-5, CHOdhfr-, Wil-2, Jurkat, Vero, Molt-4, COS-7, 293-HEK, BHK, KGH6, NSO,SP2/0-Ag 14, P3X63Ag8.653, C127, JC, LA7, ZR-45-30, hTERT, NM2C5,UACC-812, DG44 and DXB11, DHFR, HELA, CVI, COS, R1610, BALBC/3T3, HAK,BF1-1c1BPT, RAJI, HEK, EB66, or BHK.

Process for Producing a Chimeric Protein According to the Invention

According to yet another of its aspects, the present invention relatesto a process for producing a chimeric protein as previously defined,said process comprising at least the steps consisting in:

a) transfecting a host cell with a vector as defined above;

b) culturing said host cell under conditions such that the chimericprotein is produced; and

c) collecting said chimeric protein produced by said host cell at theend of step b).

1) Transfecting Step

For the purposes of the present invention, the term “transfection”refers to the process of introducing exogenous DNA (for example anexpression vector as defined above) into eukaryotic cells.

There are various methods for introducing an exogenous DNA into a cell,these methods being part of the conventional techniques known to thoseskilled in the art.

By way of example of transfection methods, mention may be made oftransfection using calcium phosphate, incorporation of the DNA to betransfected into liposomes (for eukaryotic cells, a transfection basedon lipids and polycations is preferentially used, owing to the greatersensitivity of the cells), the use of highly branched polycationicagents, called dendrimers, such as polyethyleneimine (PEI), for bindingthe DNA and transporting it into the cell (Tris is often included in thetransfection solution in order to improve membrane permeability),electroporation, heat shock, the particular properties of reagents suchas GeneCellin, and the gene gun.

Preferably, an appropriate transfection method in the context of thepresent invention is electroporation, as described, for example, byPotter et al. (2003, Curr Protoc. Mol. Biol., Chapter Unit-9.3., 1-12).

In the light of the aforementioned, the vector used preferably comprisesat least one nucleic acid comprising at least one polynucleotidesequence encoding at least one monomeric SAP-Fc or monomeric SAP-ScFcchimeric protein.

2) Step of Culturing the Transfected Cell

Once the transfection step has been carried out, the cells thus obtainedare then placed under environmental conditions, and in particular in aculture medium, capable of ensuring their survival and therefore theirmultiplication, the amplification of the vector, the induction of geneexpression and the production of the chimeric protein according to theinvention.

This step is also part of the standard knowledge of those skilled in theart.

3) Step of Recovering the Chimeric Protein

During the gene expression, the presence of a trafficking signal peptideupstream of the gene sequence encoding the chimeric protein enables thesecretion of said chimeric protein into the culture medium.

The secreted chimeric protein according to the invention therefore nolonger contains the sequence relating to the signal peptide.

The criteria for choosing the signal peptide are part of the generalknowledge of those skilled in the art and, in particular, can be basedon the D-score and the Y-max defined by the Signal IP software.

A signal peptide according to the invention can be represented by anamino acid sequence having at least 80% identity with at least one ofthe sequences described in WO 2011/114063.

More particularly, a signal peptide according to the invention may alsobe represented by an amino acid sequence having at least 80% identitywith a sequence chosen from the sequences SEQ ID NO: 20 and 22 to 27.

Preferably, the signal peptide is represented by the sequence SEQ ID NO:25.

After recovery of the cell supernatant, a step of assaying the chimericprotein using the ELISA technique can be carried out. A proteinseparation/visualization step is then required. This step can be carriedout by means of SDS-PAGE electrophoresis or Western blotting.

All these techniques are part of the standard knowledge of those skilledin the art.

4) Additional Steps

In the case where it is sought to obtain a dimeric SAP-Fc or dimericSAP-ScFc chimeric protein as previously defined, it should be noted thatthese specific architectures are naturally produced in the host cell.

Preferably, a process according to the invention can also comprise apurifying step d).

Such a purifying step is carried out using the conventional techniquesknown to those skilled in the art. In this respect, mention may be madeof purification on an affinity column coupled to the antigen, on proteinA or on protein G, or else an affinity column coupled to anti-SAPaptamers and/or aptamers against a fragment of an Fc region of a humanantibody under consideration.

In the event of a process for producing a chimeric protein according tothe invention considering the use of a step c), step d) can take placeprior to or subsequent to this step c).

In the context of a purification on an affinity column coupled to theantigen, it is possible to imagine a system comprising an anti-SAPantibody so as to isolate the chimeric proteins according to theinvention.

The purification method considered can also involve the implementationof an eluting step so as to recover the complexes formed, and thereforethe chimeric proteins according to the invention. This eluting step isalso part of the conventional techniques known to those skilled in theart.

The chemical protein according to the invention may also be producedfrom transgenic animals. According to one preferred embodiment, saidprotein is produced in the milk of non-human transgenic mammals,genetically modified to produce this chemical protein. A transgenicanimal according to the invention can be chosen from rabbits, goats,cows, camels, hamsters, mice, rats, horses, sows, dromedaries, ewes andlamas, the list not being limiting. Preferably, it involves the milkfrom a transgenic doe rabbit or a transgenic goat. The secretion of saidprotein by the mammary glands, allowing its secretion in the milk of thetransgenic mammal, involves controlling its expression in atissue-dependent manner. Such control methods are well known to thoseskilled in the art. The expression is controlled by virtue of sequenceswhich allow expression of the protein toward a particular tissue of theanimal. These are in particular the WAP, beta-casein, andbeta-lactoglobulin promoter sequences and the signal peptide sequences.The process for extracting the proteins of interest from the milk oftransgenic animals is in particular described in EP 0 264 166.

Use of a Chimeric Protein According to the Invention

As previously indicated, the present invention relates to the field ofobtaining specific chimeric protein for therapeutic use, in particularfor treating amyloidosis, in particular amyloidosis of AL type.

Consequently, according to yet another of its aspects, the presentinvention relates to a pharmaceutical composition comprising a chimericprotein according to the invention and a pharmaceutically acceptableexcipient.

As indicated above, a chimeric protein according to the invention mayhave different architectures. In this respect, a pharmaceuticalcomposition according to the invention may comprise a mixture ofchimeric proteins according to the invention having differentarchitectures. More particularly, among all the chimeric proteinsaccording to the invention which can be included in a pharmaceuticalcomposition according to the invention, mention may be made of:

-   -   the chimeric protein comprising two units, each unit comprising        a human amyloid P component and a fragment of an Fc region of a        human antibody, bonded to each other by a hinge region, the two        units being bonded to each other covalently by at least one        disulfide bridge (characterizes the dimeric SAP-Fc        architecture);    -   the chimeric protein comprising a human amyloid P component and        two fragments of an Fc region of a human antibody (i.e. first        and second fragments of an Fc region of a human antibody), the        human amyloid P component being attached to the first fragment        of an Fc region by a hinge region and the two fragments of an Fc        region, which may be identical or different, being bonded to        each other covalently by means of a bond formed from a spacer        chain and a hinge region, and form a single polypeptide chain        constituting a functional dimeric Fc region (characterizes the        monomeric SAP-ScFc architecture); and    -   the chimeric protein comprising at least two monomeric SAP-ScFc        units bonded to each other covalently by at least two disulfide        bridges (characterizes the dimeric SAP-ScFc architecture).

Preferably, a pharmaceutical composition according to the invention ispredominantly formed from chimeric proteins comprising two units eachcomprising a human amyloid P component and a fragment of an Fc region ofa human antibody, the two units being bonded to each other covalently bya spacer chain (characterizes the dimeric SAP-Fc architecture), with,for each unit, the human amyloid P component and the fragment of an Fcregion of a human antibody being bonded to each other by means of ahinge region.

In certain embodiments, a pharmaceutical composition according to theinvention may be in liquid form.

In certain embodiments, a pharmaceutical composition according to theinvention may be in solid form, said form comprising a lyophilized form.

A pharmaceutical composition according to the invention can beformulated according to standard methods such as those described inRemington: The Science and Practice of Pharmacy (Lippincott Williams &Wilkins; Twenty First Edition, 2005).

By way of pharmaceutically acceptable excipient, mention may inparticular be made of those described in Handbook of PharmaceuticalExcipients, American Pharmaceutical Association (Pharmaceutical Press;6th revised edition, 2009).

In order to treat a patient in need of said treatment, i.e. a patientsuffering from at least one of the indications considered in the presentapplication, a therapeutically effective dose of the compositionaccording to the invention can be administered.

The term “therapeutically effective dose” is intended to mean a dosewhich produces expected effects for which a composition according to theinvention is administered. The exact dose will depend on the purpose ofthe treatment, and will be verifiable by those skilled in the art usingknown techniques. The doses that can be considered can range from 0.001to 100 mg of chimeric proteins according to the invention, per kg ofbody weight (mg/kg) or more, for example 0.1, 1.0, 10 or 50 mg/kg ofbody weight, with 1 to 10 mg/kg being preferred. The dosage and theadministration frequency can be adjusted according to the response bythe treated patient, and the injection frequency.

Preferably, the chimeric protein can be administered at a dose rangingfrom 0.1 to 1000 μg/kg of body weight.

As is known in the art, adjustments given the degradation of theproteins, systemic compared with localized administration, and age,weight, general health, sex, diet, administration time, druginteractions and seriousness of the condition of the patient may benecessary, and can be easily determined by those skilled in the art bymeans of routine experimentation.

The administration of a pharmaceutical composition according to theinvention can be carried out in several ways, including, but withoutbeing limited thereto, via the local and cutaneo-mucosal route, via theenteral route or via the parenteral route.

The term “local and cutaneo-mucosal route” is intended in particular todenote the topical, intra-auricular, intravaginal, intra-uterine,inhalation, transdermal, ocular or intravesical route.

The term “enteral route” is intended in particular to denote theintrarectal, sublingual, buccal, nasal, intra-stomach or intrajejunalroute.

The term “parenteral route” is intended in particular to denote theintradermal, subcutaneous, intramuscular, intracardiac, intravascular,intravenous, intra-ocular, intra-arterial, epidural, intraspinal,extracorporeal, intrathecal, intraperitoneal, intrapleural,intraluminal, intravitreal, intracavernous, intraventricular,intra-bone, palatine, intra-articular, intracellular, pulmonary orintrafetal route.

Preferably, the administration of a pharmaceutical composition accordingto the invention can be carried out via the intravenous (IV) orsubcutaneous (SC) route according to an administration scheme derivedfrom a standard protocol used in treatment by passive immunotherapy.Other modes of administration such as local injection or aerosoladministration can also be used.

The composition of the invention can be administered concomitantly withother therapeutic agents, in particular specific treatments forovercoming the functional insufficiency or insufficiencies of the organor organs affected by the amyloid deposits.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof as a medicament.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof for eliminatingthe amyloidosis deposits in the organs.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, which, by integrating into thehuman amyloid deposit, will induce a recruitment of effector cells suchas monocyte-macrophages and polymorphonuclear cells and as a resultinduce the elimination of the amyloid deposits by phagocytosis.

According to yet another of its aspects, the present invention relatesto a chimeric protein as defined above, for use thereof for treatingamyloidosis, in particular amyloidosis of AL type.

According to yet another of its aspects, the present invention relatesto a process for treating amyloidosis, in particular amyloidosis of ALtype, comprising at least one step of administering, to an individual inneed thereof, an effective amount of at least one first active agentrepresented by a chimeric protein as previously defined.

According to one particular embodiment, said process can also comprise astep of administering, prior to, concomitantly with and/or subsequent tothe step of administering the first active agent, a second active agentdistinct from said first active agent, the second active agentpreferably being chosen from the group comprising4-[bis(chloroethyl)amino]phenylalanine (melphalan);9-fluoro-11β,17,21-trihydroxy-16a-methylpregna-1,4-diene-3,20-dione(dexamethasone); prednisone; dimethyl sulfoxide (DMSO);N-[(7S)-5,6,7,9-tetrahydro-1,2,3,10-tetramethoxy-9-oxobenzo[a]heptalen-7-yl)acetamide](colchicine);(7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione(doxorubicin); agents capable of reacting with the amyloid P component,in particular of bis-d-proline type, and more particularly the compound(R)-1-[6-[(R)-2-carboxypyrrolidin-1-yl]-6-oxohexanoyl]pyrrolidine-2-carboxylicacid); proteasome inhibitors, for example bortezomib, carfilzomib,marizomib, ixazomib, delanzomib, ONX-912 or revlimid; and a mixturethereof.

A chimeric protein according to the invention can also be identified bymeans of any technique known to those skilled in the art. In thisrespect, mention may in particular be made of the technique via couplingwith fluorophores and the microbeads as described in Neri et al. (1997)Nat Biotech, or else the techniques described in Brack et al. (2005)EJNM, Santimaria (2003) Clinical cancer res, Borsi et al. (2002) Int Jcancer, Berndorff (2006) J Nucl Med and Joseph et al. (2004) Pham Res.

Process for Identifying Amyloid Deposits

According to yet another of its aspects, a chimeric protein according tothe invention is also advantageous in that it can be taken advantage offor use as a tool for in vitro or ex vivo characterization of thepresence of an amyloidosis deposit.

According to this aspect of the invention, said chimeric protein can belabeled using a detectable molecule. For example, according to a firstvariant, said chimeric protein can be radiolabeled; preferably, thehuman amyloid P component is represented by ¹²³I-SAP. According to asecond variant, the chimeric protein can be identified by means of aradiolabeled anti-Fc antibody; for example, said anti-Fc antibody iscoupled to peroxidase.

Preferably, for obvious reasons, said anti-Fc antibody is of humanorigin.

By way of peroxidase-coupled anti-Fc, it is possible to use any antibodyavailable on the market, showing good specificity and an interactionwith the Fc part of the Fc-SAP fusion protein. By way of example,mention may be made of that sold under the name A0170 by the companySigma-Aldrich.

A chimeric protein according to the invention can also be identified bymeans of any technique known to those skilled in the art. In thisrespect, mention may in particular be made of the technique via couplingwith fluorophores and microbeads as described in Neri et al. (1997) NatBiotech, or else the techniques described in Brack et al. (2005) EJNM,Santimaria (2003) Clinical cancer res, Borsi et al. (2002) Int J cancer,Berndorff (2006) J Nucl Med and Joseph et al. (2004) Pham Res.

TABLE 2 Sequences SEQ ID NO: Type Description 1 Peptide Human amyloid Pcomponent 2 Nucleic acid Human amyloid P component 3 Peptide Fragment ofan Fc region of a human antibody 4 Nucleic acid Fragment of an Fc regionof a human antibody 5 Peptide Non-structuring peptide sequence betweenSAP and a hinge region, or spacer chain between two fragments of an Fcregion of a human antibody at the level of SAP-ScFc 6 Nucleic acidNon-structuring peptide sequence between SAP and a hinge region, orspacer chain between two fragments of an Fc region of a human antibodyat the level of SAP-ScFc 7 Peptide Secreted monomeric SAP-Fc 8 Nucleicacid Secreted monomeric SAP-Fc 9 Peptide Secreted monomeric SAP-ScFc 10Nucleic acid Secreted monomeric SAP-ScFc 11 Peptide Hinge region + thetwo fragments of an Fc region of a human antibody, bonded to each otherby a spacer chain and a hinge region of SAP-ScFc 12 Nucleic acid Hingeregion + the two fragments of an Fc region of a human antibody, bondedto each other by a spacer chain and a hinge region of SAP-ScFc 13Peptide Human IgG1 hinge region 14 Nucleic acid Human IgG1 hinge region15 Peptide Human IgG2 hinge region 16 Peptide Human IgG3 hinge region 17Peptide Human IgG3 hinge region 18 Peptide Human IgG4 hinge region 19Peptide Shortened human IgG1 hinge region 20 Peptide Natural signalpeptide of SAP 21 Nucleic acid Natural signal peptide of SAP 22 PeptideMMP1 human TIMP signal peptide 23 Peptide Human insulin signal peptide24 Peptide Human EPO signal peptide 25 Peptide MB7 signal peptide 26Peptide AMHRII signal peptide 27 Peptide XXII49 signal peptide 28Nucleic acid SAP of example 1 29 Nucleic acid Fragment of an Fc regionof a human antibody of example 1 30 Nucleic acid Monomeric SAP-Fc ofexample 1 31 Peptide Monomeric SAP-Fc of example 1 32 Nucleic acid Firstfragment of an Fc region of a human antibody of example 2 33 Nucleicacid Second fragment of an Fc region of a human antibody of example 2 34Nucleic acid Spacer chain between the first and second fragments of anFc region of a human antibody of example 2 35 Nucleic acid MonomericSAP-ScFc of example 2 36 Peptide Monomeric SAP-ScFc of example 2 37Nucleic acid First primer for SAP amplification in example 1 38 Nucleicacid Second primer for SAP amplification in example 1 39 Nucleic acidFirst primer for amplification of the fragment of an Fc region of ahuman antibody in example 1 40 Nucleic acid Second primer foramplification of the fragment of an Fc region of a human antibody inexample 1 41 Nucleic acid First primer for amplification of the firstfragment of an Fc region of a human antibody in example 2 42 Nucleicacid Second primer for amplification of the first fragment of an Fcregion of a human antibody in example 2 43 Nucleic acid First primer foramplification of the second fragment of an Fc region of a human antibodyin example 2 44 Nucleic acid Second primer for amplification of thesecond fragment of an Fc region of a human antibody in example 2 45Nucleic acid First primer for amplification of the spacer chain inexample 2 46 Nucleic acid Second primer for amplification of the spacerchain in example 2

The examples and figures which follow are presented by way ofnonlimiting illustration of the invention.

EXAMPLES

Preliminarily, it should be noted that the sequence corresponding to thehuman amyloid P component used hereinafter is identified, in particular,by means of its sequence number as considered hereinafter, to which isadded, in the N-terminal part, a specific sequence corresponding to thenatural signal peptide of said component. In the case in point, thesignal peptide considered is that represented by the amino acid sequenceSEQ ID NO: 20, or even the nucleic acid sequence SEQ ID NO: 21.

Example 1 Construction of the Monomeric SAP-Fc Vector

A) Amplification of the cDNA Fragment Encoding Human SAP:

For the construction of the monomeric SAP-Fc vector, the human amyloid Pcomponent (SAP) was amplified from human cDNA with the Phusion Taqpolymerase. The STOP codon was not amplified. A Kozak sequence was addedupstream of the starting ATG of the sequence. The sequence was borderedby 2 SalI restriction sites, added in the primers used for theamplification. What is more, in the sequence considered, only the 2exons making up the SAP are present, the intron not being in thisconstruct.

The human SAP cDNA sequence used, corresponding to the sequence SEQ IDNO: 28 hereinafter, is therefore the following:

GTCGACACCATGAACAAGCCGCTCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAAC CCTTGGTGTGGGTCGAC

The PCR primers used to amplify the SAP are:

hSAPforSal:  (SEQ ID NO: 37) acttgGTCGACaccatgaacaagccgctgctttg hSAPrevfusSal: (SEQ ID NO: 38) actagGTCGACccacaccaagggtttga.

The PCR amplification was carried out using the conventional techniquesknown to those skilled in the art. In this respect, mention may be madeof the standard protocols described in Current Protocols in MolecularBiology (Frederick M. AUSUBEL, 2000, Wiley and son Inc, Library ofCongress, USA).

B) Amplification of the cDNA Fragment Encoding the Fragment of an FcRegion of a Human Antibody

The nucleic acid encoding the fragment of an Fc region of a humanantibody (with its STOP codon), also including a nucleic sequencecorresponding to a hinge region in the N-terminal region of said nucleicacid, was amplified from total cDNA extracted from human bone marrow.The Fc domain considered is that of a human IgG1 (IGHG1*03). Theamplification of the Fc domain sequence was carried out with the PhusionTaq polymerase. The Fc fragment was bordered by 2 restriction sites,XhoI and BspEI, added in the primers during the amplification.

The cDNA sequence encoding the considered fragment of an Fc region of ahuman antibody, corresponding to the sequence SEQ ID NO: 29 hereinafter,is therefore the following:

ATACTCTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAATGAGTGCTCC GGACAGAT

The PCR primers used to amplify the considered fragment of an Fc regionof a human antibody are:

hG1hingeforfusXho:  (SEQ ID NO: 39) CTCGAGcccaaatcttgtgacaa hG1CH3rev BspE I:  (SEQ ID NO: 40) TCCGGAgcactcatttacccggagac.

C) Construction of the Monomeric SAP-Fc Vector

The SAP and Fc fragments are firstly cloned into the commercial vectorpGEM®-T Easy (Promega) (see FIG. 4 hereinafter) so as to sequence them(pGEMT-SAP and pGEMT-Fc).

The fragment encoding human SAP was cleaved and isolated from thepGEMT-SAP vector using the SalI restriction enzyme (one site on eachside of the fragment) and then inserted into the pGEMT-Fc vectorupstream of the fragment encoding the Fc domain cleaved beforehand usingthe XhoI restriction enzyme (compatible with SalI).

Once the monomeric SAP-Fc had been established, cleavage with the SalIand BspEI restriction enzymes made it possible to insert the monomericSAP-Fc fragment into the pCpGfree expression vector (invivogen), (seeFIG. 5 hereinafter) digested with the same pair of enzymes, saidexpression vector having been modified beforehand so as to contain theSalI and BspEI restriction sites in the original multiple cloning siteand also a functional neomycin resistance cassette.

Complete sequencing was then carried out using a method derived from theSanger method (Sanger F, Nicklen S, Coulson A R, PNAS, 1977). The DNA isprepared so as to have fragments of all sizes, the last base of which isone of the 4 ddNTPs, labeled with a fluorochrome, which blocks thepolymerization reaction. The fragments migrate according to their sizesin the capillary tube, and the various fluorochromes are excited by alaser which makes it possible to establish the sequence. The sequencingreaction requires, in addition to the DNA to be sequenced, the forwardor reverse primer, the buffer and the BigDye® (Applied Biosystems) whichcontains the DNA polymerase, the dNTPs and the ddNTPs. The PCR programis the following: 96° C. for 1 minute, then 25 cycles composed of adehybridization step at 96° C. for 10 seconds, then a primerhybridization step at 50° C. for 5 seconds, followed by an elongationstep at 60° C. for 4 min.

In order to eliminate all the constituents which can interfere duringthe migration in the capillary tubes, the sequence products are purifiedon Sephadex™ G50 gel (GE Healthcare). The Sephadex powder is distributedin the wells of the filtration plate (Millipore) and then left for 3hours with 300 μl of water. The excess water is removed bycentrifugation for 3 min at 910 g.

Next, the sequence products are deposited in the wells on the gel,centrifuged for 3 min at 910 g and recovered in a sequencing plate. Thesequencing is carried out on an ABI 3130 automatic sequencer (AppliedBiosystems).

The nucleic acid sequence of monomeric SAP-Fc, corresponding to thesequence SEQ ID NO: 30, is the following:

ATGAACAAGCCGCTCCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAATGA

The corresponding protein sequence of the monomeric SAP-Fc,corresponding to the sequence SEQ ID NO: 31, is the following:

MNKPLLWISVLTSLLEAFAHTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK-

The corresponding protein sequence of the secreted monomeric SAP-Fc isthe following sequence SEQ ID NO: 7:

HTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK-

Example 2 Construction of the Monomeric SAP-ScFc Vector

A) Amplification of the DNA Fragment Encoding Human SAP:

See example 1.A) above.

B) Amplification of the First Fragment of cDNA Encoding the FirstFragment of an Fc Region of a Human Antibody

The nucleic acid encoding the first fragment of an Fc region of a humanantibody was amplified from a laboratory vector containing the cDNA of ahuman IgG1 (IGHG1*03). The amplification of the Fc domain sequence wascarried out with the Phusion Taq polymerase. The Fc fragment wasbordered by 2 restriction sites, XhoI and HindIII, added in the primersduring the amplification. The STOP codon was not amplified.

The cDNA sequence encoding the first fragment of an Fc region of a humanantibody, corresponding to the sequence SEQ ID NO: 32 hereinafter, isthe following sequence:

GCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGG TAAGCTT

The PCR primers used to amplify the sequence of the fragment of an Fcregion of a human antibody are:

hG1hingeforfusXho:  (SEQ ID NO: 41) atactCTCGAGcccaaatcttgtgacaa hG1CH3revfusHind:  (SEQ ID NO: 42) atctgAAGCTTacccggagacagggaga.

C) Amplification of the Second Fragment of DNA Encoding the SecondFragment of an Fc Region of a Human Antibody:

The nucleic acid encoding the second fragment of an Fc region of a humanantibody, also including a nucleic sequence corresponding to a hingeregion in the N-terminal region of said nucleic acid, was bordered by 2restriction sites, BglII and BspEI, added in the primers during theamplification. The STOP codon was amplified for this second fragment ofan Fc region of a human antibody.

The cDNA sequence encoding the second fragment of an Fc region of ahuman antibody, corresponding to the sequence SEQ ID NO: 33 hereinafter,is therefore the following:

AGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCG GGTAAATGAGTGCTCCGGA

The PCR primers used to amplify the sequence of the second fragment ofan Fc region of a human antibody are:

hGlhingeforfusBgI:  (SEQ ID NO: 43) aagtaAGATCTgagcccaaatcttgtgacaa hG1CH3revBspE:  (SEQ ID NO: 44) atctgTCCGGAgcactcatttacccggagac.

D) Amplification of the Spacer Chain Between the Two Fragments of an FcRegion of a Human Antibody:

The sequence of the spacer chain was amplified from a laboratory vectorcontaining the sequence of an ScFv. This sequence encodes a peptide of15 amino acids (Gly4Ser repeated 3 times). The amplification of thespacer chain was carried out by means of the Phusion Taq polymerase. Thesequence of the spacer chain ends with a BamHI restriction site alreadypresent in the laboratory vector. The HindIII restriction site is addedby the Forward primer during the amplification.

The sequence encoding the spacer chain, corresponding to the sequenceSEQ ID NO: 34 hereinafter, is therefore the following:

AAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGC GGATCC

The PCR primers used to amplify the sequence of the linker are:

LinkforHind III:  (SEQ ID NO: 45) AAGCTTggtggaggcggttcagg  LinkrevBHI: (SEQ ID NO: 46) GGATCCgccaccgccagagcca.

E) Construction of the Monomeric SAP-ScFc Vector

The various fragments making up the monomeric SAP-ScFc were firstlycloned independently into the commercial vector pGEMT-easy (Promega)(see FIG. 4 hereinafter) so as to sequence them. This produced thevectors respectively called: pGEMT-SAP, pGEMT-first Fc, pGEMT-linker andpGEMT-second Fc.

The expression vectors considered were modified beforehand so as tocontain the Xho/Hind (for the first Fc fragment) and Bg1/BspE1 (for thesecond Fc fragment) restriction sites in the original multiple cloningsite and also a functional neomycin resistance cassette.

The fragment encoding the human SAP present in the pGEMT-SAP vector wascleaved and isolated using the SalI restriction enzyme (one site on eachside of the fragment) and then inserted into the pGEMT-first Fc vectorcontaining the sequence of the first fragment of an Fc region of a humanantibody, upstream of said fragment, previously cleaved using the XhoIrestriction enzyme.

The HindIII/NotI cleaved linker (the NotI site being present in 3′ ofthe multiple cloning site of the pGEMT-Easy vector) was then addeddownstream of the first fragment of an Fc region of a human antibody inthe pGEMT-SAP-first Fc vector following digestion using the HindIII andNotI restriction enzymes.

The second fragment of an Fc region of a human antibody was then cleavedand isolated from the pGEMT-second Fc vector using the BglII/NotIenzymes and then inserted into the pGEMT-SAP-first Fc-linker vectordigested using the BamHI/NotI restriction enzymes.

Once the SAP-ScFc had been established, cleavage using the SalI andBspeI restriction enzymes made it possible to insert the SAP-ScFcfragment into the pCpG expression vector (invivogen) previously modifiedto contain the SalI and BspEI restriction sites in the original multiplecloning site and also a functional neomycin resistance cassette (seeFIG. 4 hereinafter) digested with the same pair of enzymes.

Complete sequencing was then carried out.

The nucleic acid sequence of the monomeric SAP-ScFc, corresponding tothe sequence SEQ ID NO: 35 hereinafter, is the following:

ATGAACAAGCCGCTCCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCGGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTG TCTCCGGGTAAATGA

The corresponding protein sequence of the monomeric SAP-ScFc,corresponding to the sequence SEQ ID NO: 36 hereinafter, is thefollowing:

MNKPLLWISVLTSLLEAFAHTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKLGGGGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSL SPGK-

The corresponding protein sequence of the secreted monomeric SAP-ScFc,corresponding to the sequence SEQ ID NO: 9 hereinafter, is thefollowing:

HTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKLGGGGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK-

Example 3 Production of SAP-Fc/ScFc Chimeric Proteins According to theInvention

A) Transformation of SP2/0, CHO and YB2/0 Cells by Electroporation

The transfection is carried out using the Nucleofector™ electroporationprotocol (Lonza). The cells in the exponential phase are centrifuged for5 min at 300 g and resuspended in PBS. After counting, the requiredamount is pelleted by centrifugation (300 g, 5 min) and taken up in 100μl of Nucleofector™ solution V buffer. 2.5×10⁶ SP2/0 cells or 1×10⁶ CHOcells are transfected with 2.5 μg of linearized vector. Afterelectroporation, the cells are put back into complete medium anddistributed in 96-well plates at 1000 cells per well for the SP2/0 cellsand 100 cells per well for the CHO cells. The optimal clonalityconditions were established according to the efficiency of theelectroporation program chosen and the nature of the line used. Theselection of the clones having stably integrated the expression vectoris carried out by adding neomycin (G418) at 1 mg/ml final concentration24 h after the transfection.

It should be noted that the dimerization of the monomeric SAP-Fc andSAP-ScFc proteins takes place naturally in the transformed cells, aspreviously mentioned.

After 15-20 days of culture, the supernatants of the G418-resistantclones are removed and then tested by ELISA in order to evaluate thelevel of production of the recombinant protein (detection of the humanFc). The selected clones are amplified in 24-well plates and then T25flasks for other ELISA assays and a part is frozen in liquid nitrogen infreezing medium containing 10% of DMSO and 20% of FCS.

Protocol for Assaying SAP-Fc and SAP-ScFc by ELISA:

Firstly, MaxiSorp™ plates (NUNC) are coated with an anti-human IgGprimary antibody (1 μg/ml, Beckman Coulter) overnight at 4° C. After 3washes with PBS/0.05% tween 20, 50 μl of the samples diluted in completemedium are incubated for 2 h at 37° C. At the same time, a standardrange of human IgG diluted in complete medium is incubated. After 3washes, an anti-IgG antibody (Beckman Coulter) coupled to alkalinephosphatase (1 μg/ml) is added and incubated for 1 h 30 at 37° C. Aftera final series of washing, a volume of 100 μl of the alkalinephosphatase substrate is added and the reaction is then stopped after afew minutes using 3M NaOH. The plate is read by spectrometry at 405 nm.

B) Purification of the SAP-Fc/SAP-ScFc Chimeric Proteins Obtained

B-1) Purification on Protein A

The SAP-Fc/SAP-ScFc chimeric proteins obtained are then purified byaffinity chromatography on an ÄKTA_(FPLC) system (GE Healthcare) usingprotein A affinity columns (Pierce) owing to the strong affinity ofprotein A for the Fc segments and usable owing to the presence of Fcregion fragments in the chimeric proteins according to the invention.The UV detector located downstream of the column makes it possible tomonitor the progression; when the absorption of the nonretained phasedescends to a threshold value, the protein is eluted with 0.1 M glycineat pH 2.6. The various fractions are collected according to thechromatogram peaks. The eluates obtained are then neutralized with Trisat pH 8.8.

The purified proteins are concentrated by means of Amicon® Ultra4 30 kfilters (Millipore), which make it possible to eliminate moleculeshaving a size less than 30 kDa. The solutions are placed in the filtersand centrifuged at 4000 g for the time required to obtain the desiredvolume and the desired concentration.

Results:

The results of this step of purification on protein A are illustrated inFIG. 6 hereinafter.

B-2) Detection of the SAP-Fc/SAP-ScFc Chimeric Proteins by WesternBlotting

Denaturing Gel

The purified proteins (or culture supernatants) are mixed with a volumeof loading blue containing β-mercaptoethanol (Bio Rad) and boiled for 5min. They are then migrated by electrophoresis on a polyacrylamide gel(SDS-PAGE) composed of a stacking phase at 7.5% and a separating phaseat 10%. The proteins are then transferred onto a PVDF membrane andsaturated with 5% milk. They are then incubated for 1 h at ambienttemperature in the presence of the mouse anti-SAP (Abcam) or anti-IgGantibody coupled to HRP (Beckman Coulter) (1 μg/ml). The anti-SAPantibody is revealed with a goat anti-mouse IgG secondary antibodycoupled to HRP (Santa Cruz) (0.2 μg/ml). The chemiluminescence reactionis triggered by adding the ECL substrate (Pierce) and revealed on anautoradiographic film (Kodak).

Semi-Native Gel

The proteins are mixed with a volume of loading blue withoutβ-mercaptoethanol and then migrated in an SDS-12% PAGE gel. The rest ofthe protocol is the same as for the denaturing gel.

Results:

The results are illustrated in FIG. 7.

The band at 75 kDa corresponds to the monomeric SAP-ScFc architecture.The band at 100 kDa corresponds to the dimeric SAP-Fc architecture.

Example 4 Recognition of the Amyloid Substance

A) Test for In Vitro Binding of the SAP-Fc/SAP-ScFc Chimeric Proteins onSections of Human Amyloid Heart

The SAP-Fc/ScFc chimeric proteins according to the invention are broughtinto contact with sections of human amyloid heart, in the presence ofcalcium and of DNAse I.

The amyloid organs are provided by the reference center for ALamyloidosis and other monoclonal Ig deposit diseases. The organfragments are fixed on a Cryomatrix™ gel (Thermo Scientific), then cutat −20° C. onto SuperFrost® Plus slides (Thermo Scientific) at athickness of 8 μm. The slides are stored at −80° C.

The slides are then dried at ambient temperature and then fixed inacetone at −20° C. for 15 min. A treatment with DNAse I (4 U/μl) iscarried out at ambient temperature for 15 min, followed by two rapidwashes and two washes for 5 min with PBS. The DNAse treatment makes itpossible to prevent attachment of the SAP which has a natural affinityfor DNA. The primary antibodies, which will serve as a positive control,are then added to the slides at 5 μg/ml in PBS and incubated for 1 h ina humid chamber at 37° C. The SAP-Fc and SAP-ScFc proteins are dilutedin PBS (5 μg/ml) containing CaCl₂ at 2.2 mM. After washing, thesecondary antibodies (rabbit anti-human IgG Fc, Dako or mouse anti-humanSAP, Abcam) coupled to fluorochromes and diluted in PBS to 1 μg/ml areadded and incubated for 30 min at ambient temperature.

Results:

The results obtained confirm the fact that the SAP-Fc/SAP-ScFc chimericproteins according to the invention retain their ability to bind to theamyloidosis deposits and do not bind to healthy tissues.

B) Test for In Vivo Binding of the SAP-Fc/SAP-ScFc Chimeric Proteins ona Murine Model of AA Amyloidosis

B-1) Preparation of a Murine Model of AA Amyloidosis

On D0, a solution comprising I.V 200 μl of AEF (i.e. ground SaM ApoAIIamyloidosis spleen material) is injected intravenously and 200 μl of 1%silver nitrate are injected subcutaneously, into a mouse (Balb/c orC57/B16).

On D7 and D14, a solution comprising 100 μl of 1% silver nitrate isinjected subcutaneously.

On D21, the animal is sacrificed and the spleen and liver are removed.

Sections of these organs are cut, and staining with Congo red is carriedout on said sections in order to recognize the amyloidosis deposits.

Results:

The results obtained characterize without any doubt the presence ofamyloidosis deposits on the sections of organs derived from the murinemodel previously described, said deposits being absent on healthy mice.

B-2) Test for Binding of the SAP-Fc/SAP-ScFc Chimeric Proteins Accordingto the Invention

The same murine model of AA amyloidosis as the one described in pointB-1) above is considered.

On D21, in place of the sacrifice step, 2 mg of a solution comprisingthe SAP-Fc or SAP-ScFc chimeric proteins according to the invention or 1mg of human SAP are intravenously injected. In parallel, other mice areinjected with PBS as a control.

On D24, the animal is sacrificed and the spleen and liver are removed.

The slides are prepared as previously described. The amyloid depositsare revealed by staining with Congo red.

The presence of SAP-Fc or SAP-ScFc associated with the amyloid depositsis observed by means of labeling with FITC-coupled anti-human IgG Fc(Dako). When possible, double labeling with the Congo red is carried outin order to be sure of the colocalization of the deposits.

Finally, anti-human SAP labeling was also carried out on certain slidesof the various organs/animals.

Results:

The results obtained confirm:

-   -   the presence of characteristic amyloid deposits in the spleen        and the liver of the animals where the AA amyloidosis was        triggered,    -   the capacity of the SAP-Fc/SAP-ScFc chimeric proteins according        to the invention to bind to the amyloid deposits (with        colocalization on Congo red),    -   the specificity of the anti-human Fc IgG labeling (absence of        labeling on the mice that were amyloid but injected with human        SAP without Fc),    -   the specificity of the binding of the SAP-Fc/SAP-ScFc to the        amyloid deposits (total absence of labeling on the slides of        healthy mice).

Example 5 Evaluation of the In Vivo Therapeutic Efficacy of theSAP-Fc/SAP-ScFc Chimeric Proteins on AA Amyloidosis in Balb/c Mice

1) Materials and Methods

The induction of AA amyloidosis in Balb/c mice is carried out accordingto the protocol defined in FIG. 9 hereinafter.

As emerges from this FIG. 9, various compounds are tested. Each time,the compound tested is injected into the Balb/c mice one week after thefinal injection of AgNO₄.

The compounds tested are an SAP-ScFc chimeric protein according to theinvention (3 mg), an SAP-Fc chimeric protein according to the invention(3 mg), an anti-FVIII irrelevant IgG1 immunoglobulin (“IgIR”, isotypecontrol) (6 mg) or else PBS buffer (negative control).

Sections of the organs from the mice described above, in particular thespleen, are cut, and staining with Congo red is carried out on saidsections in order to recognize the deposits of amyloidosis, so as toquantify said deposits.

2) Results:

As emerges from FIG. 10, the amyloidosis deposits are significantlyweaker in the Balb/c mice treated with SAP-Fc or SAP-ScFc.

The results obtained therefore confirm the capacity of theSAP-Fc/SAP-ScFc chimeric proteins according to the invention:

-   -   to bind to the amyloid deposits, and    -   to eliminate the AA amyloidosis deposits.

The results obtained also attest that it is indeed the SAP fragmentpresent in the chimeric proteins according to the invention which allowsthem to actually bind to the amyloid deposits. This emerges from theinability of the IgIR compound to bind to the amyloid deposits. Indeed,this IgIR compound admittedly comprises at least one fragment of an Fcregion of a human antibody similar to that present in the chimericproteins according to the invention, but it is on the other hand devoidof the SAP fragment.

Example 6 Other Evaluation of the In Vivo Therapeutic Efficacy of theSAP-Fc/SAP-ScFc Chimeric Proteins on AA Amyloidosis in VH-LMP2A Mice

1) Materials and Methods

The induction of AA amyloidosis in VH-LMP2A mice is carried outaccording to the protocol defined in FIG. 9 above.

The compounds tested are a chimeric protein according to the invention(SAP-ScFc), an SAP protein as such (i.e. devoid of the fragment of an Fcregion of a human antibody), or else PBS buffer.

The VH-LMP2A mice have the particularity of being devoid of the abilityto produce antibodies. In fact, a decrease in the amyloidosis depositssubsequent to the injection of a specific compound will reflect saidspecific compound's own capacity to effectively recruit the effectorcells, in particular the neutrophil polymorphonuclear cells and themonocyte-macrophages, involved in the elimination of the amyloiddeposits.

Sections of the organs from the mice described above, in particular thespleen, are cut, and staining with Congo red is carried out on saidsections in order to recognize the amyloidosis deposits, so as toquantify said deposits.

2) Results:

As emerges from FIG. 11, the amyloidosis deposits are significantlyreduced in the VH-LMP2A mice treated with the SAP-ScFc chimeric proteinsaccording to the invention.

On the other hand, as emerges from FIG. 11, no decrease in theamyloidosis deposits is observed in the case of the SAP protein as such,i.e. devoid of the fragment of an Fc region of a human antibody.

The results obtained therefore confirm the capacity of theSAP-Fc/SAP-ScFc chimeric proteins according to the invention:

-   -   to bind to the amyloid deposits, and    -   to eliminate the AA amyloidosis deposits, and therefore to        effectively recruit the effector cells, in particular the        neutrophil polymorphonuclear cells and the monocyte-macrophages,        involved in the elimination of these amyloid deposits.

The results obtained also attest that it is indeed the fragment of an Fcregion of a human antibody present in the chimeric proteins according tothe invention which enables this effective recruitment of the effectorcells.

SEQUENCES: SEQ ID NO: 1: (Protein = human SAP)HTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIK PLVWVSEQ ID NO: 2: (DNA = human SAP)CACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAA CCCTTGGTGTGGGTCSEQ ID NO: 3: (Protein = fragment of an Fc region of a human antibody)APELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVM HEALHNHYTQKSLSLSPGKSEQ ID NO: 4: (DNA = fragment of an Fc region of a human antibody)GCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGG TAAATGASEQ ID NO: 5: (Protein = Non-structuring peptidesequence between SAP and a hinge region, or spacerchain between two fragments of an Fc region at the level of SAP-ScFc)(GGGGS)n, with n between 1 and 5 SEQ ID NO: 6: (DNA =Non-structuring peptidesequence between SAP and a hinge region, or spacerchain between two fragments of an Fc region at thelevel of characterizes SAP-ScFc)(CTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCG)m, with m between 1 and 5SEQ ID NO: 7: (Protein = Secreted monomeric SAP-Fc)HTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 8: (DNA =Secreted monomeric SAP-Fc)CACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGT CTCCGGGTAAATGASEQ ID NO: 9: (Protein = Secreted monomeric SAP-ScFc)HTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKLGGGGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 10: (DNA =Secreted monomeric SAP-ScFc)CACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCGGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGG GTAAATGASEQ ID NO: 11: (Protein = hinge region + twofragments of an Fc region of a human antibody,bonded to each other by a bond (spacer chain +hinge region) of SAP-ScFc)EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKLGGGGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 12: (DNA = hinge region +two fragments of an Fc region of a human antibody, bonded to each other by a bond (spacer chain + hinge region)  of SAP-ScFc)GAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCC AAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCGGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAATGASEQ ID NO: 13: (Protein = Human IgG1 hinge region) EPKSCDKTHTCPPCPSEQ ID NO: 14: (DNA = Human IgG1 hinge region) CTCACACATGCCCACCGTGCCCASEQ ID NO: 15: (Protein = Human IgG2 hinge region) ERKCCVECPPCPSEQ ID NO: 16: (Protein = Human IgG3 hinge region) ELKTPLGDTTHTCPRCPSEQ ID NO: 17: (Protein = Human IgG3 hinge region) EPKSCDTPPPCPRCPSEQ ID NO: 18: (Protein = Human IgG4 hinge region) ESKYGPPCPSCPSEQ ID NO: 19: (Protein = Shortened IgG1 hinge  region (SEQ ID NO: 13))DKTHTCPPCP SEQ ID NO: 20: (Protein = Natural signal peptide of SAP)MNKPLLWISVLTSLLEAFA SEQ ID NO: 21: (DNA = Natural signal peptide of SAP)ATGAACAAGCCGCTCCTTTGGATCTCTGTCCTCACCAGCCTCCTGGA AGCCTTTGCTSEQ ID NO: 22: (Protein = MMP1 human TIMP signal peptide (=uniprot P01033)) MAPFEPLASGILLLLWLIAPSRA SEQ ID NO: 23: (Protein =Human insulin signal peptide (= uniprot P01308))MALWMRLLPLLALLALWGPDPAAA SEQ ID NO: 24: (Protein =Human EPO signal peptide (= uniprot P01588)) MGVHECPAWLWLLLSLLSLPLGLPVLGSEQ ID NO: 25: (Protein = MB7 signal peptidederived from WO 2011/114063) MRWSWIFLLLLSITSANASEQ ID NO: 26: (Protein = AMHRII signal peptidederived from WO 2011/114063) MRWSWIFLFLLSITASVHCSEQ ID NO: 27: (Protein = XXII49 signal peptidederived from WO 2011/114063) MAWVWTLLFLMAAAQSAQA SEQ ID NO: 28: (DNA =SAP from example 1) GTCGACACCATGAACAAGCCGCTCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAC SEQ ID NO: 29: (DNA =fragment of an Fc region of a human antibody from example 1)ATACTCTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAATGAGTGCTCCGGACAGAT SEQ ID NO: 30: (DNA = Monomeric SAP-Fc fromexample 1) ATGAACAAGCCGCTCCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTC TCCCTGTCTCCGGGTAAATGASEQ ID NO: 31: (Protein = Monomeric SAP-Fc from example 1)MNKPLLWISVLTSLLEAFAHTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSL SLSPGK-SEQ ID NO: 32: (DNA = First fragment of an Fcregion of a human antibody from example 2)GCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGG TAAGCTTSEQ ID NO: 33: (DNA = Second fragment of an Fcregion of a human antibody from example 2)AGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTA AATGAGTGCTCCGGASEQ ID NO: 34: (DNA = Spacer chain between thefirst and second fragments of an Fc region of ahuman antibody from example 2)AAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCG GATCCSEQ ID NO: 35: (DNA = Monomeric SAP-ScFc from example 2)ATGAACAAGCCGCTCCTTTGGATCTCTGTCCTCACCAGCCTCCTGGAAGCCTTTGCTCACACAGACCTCAGTGGGAAGGTGTTTGTATTTCCTAGAGAATCTGTTACTGATCATGTAAACTTGATCACACCGCTGGAGAAGCCTCTACAGAACTTTACCTTGTGTTTTCGAGCCTATAGTGATCTCTCTCGTGCCTACAGCCTCTTCTCCTACAATACCCAAGGCAGGGATAATGAGCTACTAGTTTATAAAGAAAGAGTTGGAGAGTATAGTCTATACATTGGAAGACACAAAGTTACATCCAAAGTTATCGAAAAGTTCCCGGCTCCAGTGCACATCTGTGTGAGCTGGGAGTCCTCATCAGGTATTGCTGAATTTTGGATCAATGGGACACCTTTGGTGAAAAAGGGTCTGCGACAGGGTTACTTTGTGGAAGCTCAGCCCAAGATTGTCCTGGGGCAGGAACAGGATTCCTATGGGGGCAAGTTTGATAGGAGCCAGTCCTTTGTGGGAGAGATTGGGGATTTGTACATGTGGGACTCTGTGCTGCCCCCAGAAAATATCCTGTCTGCCTATCAGGGTACCCCTCTCCCTGCCAATATCCTGGACTGGCAGGCTCTGAACTATGAAATCAGAGGATATGTCATCATCAAACCCTTGGTGTGGGTCGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTATAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTGTCTCCGGGTAAGCTTGGTGGAGGCGGTTCAGGCGGAGGTGGCTCTGGCGGTGGCGGATCTGAGCCCAAATCTTGTGACAAAACTCACACATGCCCACCGTGCCCAGCACCTGAACTCCTGGGGGGACCGTCAGTCTTCCTCTTCCCCCCAAAACCCAAGGACACCCTCATGATCTCCCGGACCCCTGAGGTCACATGCGTGGTGGTGGACGTGAGCCACGAAGACCCTGAGGTCAAGTTCAACTGGTACGTGGACGGCGTGGAGGTGCATAATGCCAAGACAAAGCCGCGGGAGGAGCAGTACAACAGCACGTACCGTGTGGTCAGCGTCCTCACCGTCCTGCACCAGGACTGGCTGAATGGCAAGGAGTACAAGTGCAAGGTCTCCAACAAAGCCCTCCCAGCCCCCATCGAGAAAACCATCTCCAAAGCCAAAGGGCAGCCCCGAGAACCACAGGTGTACACCCTGCCCCCATCCCGGGAGGAGATGACCAAGAACCAGGTCAGCCTGACCTGCCTGGTCAAAGGCTTCTATCCCAGCGACATCGCCGTGGAGTGGGAGAGCAATGGGCAGCCGGAGAACAACTACAAGACCACGCCTCCCGTGCTGGACTCCGACGGCTCCTTCTTCCTCTACAGCAAGCTCACCGTGGACAAGAGCAGGTGGCAGCAGGGGAACGTCTTCTCATGCTCCGTGATGCATGAGGCTCTGCACAACCACTACACGCAGAAGAGCCTCTCCCTG TCTCCGGGTAAATGASEQ ID NO: 36: (Protein = Monomeric SAP-ScFc from example 2)MNKPLLWISVLTSLLEAFAHTDLSGKVFVFPRESVTDHVNLITPLEKPLQNFTLCFRAYSDLSRAYSLFSYNTQGRDNELLVYKERVGEYSLYIGRHKVTSKVIEKFPAPVHICVSWESSSGIAEFWINGTPLVKKGLRQGYFVEAQPKIVLGQEQDSYGGKFDRSQSFVGEIGDLYMWDSVLPPENILSAYQGTPLPANILDWQALNYEIRGYVIIKPLVWVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKLGGGGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSL SPGKSEQ ID NO: 37: (Nucleic acid = First primer forSAP amplification in example 1) ACTTGGTCGACACCATGAACAAGCCGCTGCTTTGSEQ ID NO: 38: (Nucleic acid = Second primer forSAP amplification in example 1) ACTAGGTCGACCCACACCAAGGGTTTGASEQ ID NO: 39: (Nucleic acid = First primer forthe amplification of the fragment of an Fc regionof a human antibody in example 1) CTCGAGCCCAAATCTTGTGACAASEQ ID NO: 40: (Nucleic acid = Second primer forthe amplification of the fragment of an Fc regionof a human antibody in example 1) TCCGGAGCACTCATTTACCCGGAGACSEQ ID NO: 41: (Nucleic acid = First primer forthe amplification of the first fragment of anFc region of a human antibody in example 2) ATACTCTCGAGCCCAAATCTTGTGACAASEQ ID NO: 42: (Nucleic acid = Second primer forthe amplification of the first fragment of anFc region of a human antibody in example 2) ATCTGAAGCTTACCCGGAGACAGGGAGASEQ ID NO: 43: (Nucleic acid = First primer forthe amplification of the second fragment of anFc region of a human antibody in example 2)AAGTAAGATCTGAGCCCAAATCTTGTGACAA SEQ ID NO: 44: (Nucleic acid =Second primer for the amplification of the second fragment of anFc region of a human antibody in example 2)ATCTGTCCGGAGCACTCATTTACCCGGAGAC SEQ ID NO: 45: (Nucleic acid =First primer for the amplification of the spacer chain in example 2)AAGCTTGGTGGAGGCGGTTCAGG SEQ ID NO: 46: (Nucleic acid = Second primer forthe amplification of the spacer chain in example 2)GGATCCGCCACCGCCAGAGCCA

1.-29. (canceled)
 30. A chimeric protein comprising at least one humanamyloid P component and at least one fragment of an Fc region of a humanantibody, wherein the human amyloid P component and the fragment of anFc region are bonded to each other by a hinge region.
 31. The chimericprotein as claimed in claim 30, wherein the human amyloid P componentcomprises an amino acid sequence having at least 80% identity with SEQID NO:
 1. 32. The chimeric protein as claimed in claim 30, wherein theFc region of the antibody is the Fc region of a human immunoglobulin,preferably the Fc region of an IgG, more preferably the Fc region of anIgG1 or of an IgG2, and even more preferably the Fc region of an IgG1.33. The chimeric protein as claimed in claim 30, wherein the fragment ofan Fc region of a human antibody comprises at least one amino acidsequence having at least 80% identity with SEQ ID NO:
 3. 34. Thechimeric protein as claimed in claim 30, wherein said Fc regioncomprises at least two modifications in the amino acid sequence, namely:(i) a modification in the amino acid sequence selected from the groupconsisting of 378V, 378T, 434Y and 434S, and (ii) at least onemodification in the amino acid sequence selected from the groupconsisting of 2260, 230S, 230T, 230L, 241 L, 264E, 307P, 315D, 330V,362R, 378V, 378T, 389T, 389K, 434Y and 434S, wherein the numbering ofthe amino acids of the Fc region is that of the EU index proposed byKabat, and wherein the modification (i) does not occur at the same aminoacid position as the modification (ii).
 35. The chimeric protein asclaimed in claim 30, wherein the hinge region comprises at least oneamino acid sequence having at least 60% identity, preferably at least80% identity, with a sequence selected from the SEQ ID NOs: 13 and 15 to18, preferably SEQ ID NO:
 13. 36. The chimeric protein as claimed inclaim 30, wherein said chimeric protein further comprises, between thehinge region and the amyloid P component, at least one non-structuringpeptide sequence, preferably SEQ ID NO:
 5. 37. The chimeric protein asclaimed in claim 30, wherein said chimeric protein comprises at leasttwo units, each unit comprising at least one human amyloid P componentand at least one fragment of an Fc region of a human antibody bonded toeach other by a hinge region, wherein the two units are bonded to eachother by at least one disulfide bridge, and wherein the fragments of anFc region of a human antibody are identical or different.
 38. Thechimeric protein as claimed in claim 30, wherein said chimeric proteincomprises at least one human amyloid P component and at least twofragments of an Fc region of a human antibody, which may be identical ordifferent, wherein said human amyloid P component and the first fragmentare bonded to each other by a first hinge region, wherein the first andsecond fragments of an Fc region are bonded to each other covalently bymeans of a bond formed from a spacer chain and a second hinge region,wherein the first hinge region and the second hinge region are identicalor different, and wherein the first and second fragments of an Fc regionform a single polypeptide chain constituting a functional dimeric Fcregion.
 39. The chimeric protein as claimed in claim 38, wherein thespacer chain is represented by at least one amino acid sequence SEQ IDNO:
 5. 40. A nucleic acid comprising at least one polynucleotidesequence encoding at least one chimeric protein as defined in claim 30.41. A vector comprising a nucleic acid as defined in claim
 40. 42. Ahost cell transfected with a vector as defined in claim
 41. 43. Aprocess for producing a chimeric protein as defined in claim 30, saidprocess comprising: a) transfecting a host cell with a vector; b)culturing said host cell under conditions such that the chimeric proteinis produced; and c) collecting said chimeric protein produced by saidhost cell in step b).
 44. The process as claimed in claim 43, whereinthe host cell is a eukaryotic cell, preferably a cell selected from thegroup consisting of the following cells: YB2/0, in particular the linedeposited at the “American Type Culture Collection” under ATCC No.CRL-1662, SP2/0, YE2/0, 1R983F, Namalwa, PER.C6, CHO cell lines, inparticular CHO-K-1, CHO-Lecl0, CHO-Lecl, CHO-Lecl3, CHO Pro-5, CHOdhfr-, Wil-2, Jurkat, Vero, Molt-4, COS-7, 293-HEK, BHK, KGH6, NSO,SP2/0-Ag 14, P3X63Ag8.653, C127, JC, LA7, ZR-45-30, hTERT, NM2C5,UACC-812, DG44 and DXB11, DHFR, HELA, CVI, COS, R1610, BALBC/3T3, HAK,BF1-1c1BPT, RAJI, HEK, EB66, or BHK.
 45. A pharmaceutical compositioncomprising a chimeric protein as defined in claim 30, and apharmaceutically acceptable excipient.
 46. A process for treatingamyloidosis, in particular amyloidosis of AL type, comprising at leastone step of administering, to an individual in need thereof, aneffective amount of at least one first active agent represented by achimeric protein as defined in claim
 30. 47. A process for treatingamyloidosis, in particular amyloidosis of AL type, comprising at leastone step of administering, to an individual in need thereof, aneffective amount of at least one first active agent represented by acomposition as defined in claim
 45. 48. The process as claimed in claim46, further comprising a step of administering, prior to, concomitantlywith and/or subsequent to the step of administering the first activeagent, at least one second active agent distinct from said first activeagent, the second active agent preferably being chosen from the groupconsisting of 4-[bis(chloroethyl)amino]phenylalanine;9-fluoro-11β,17,21-trihydroxy-16a-methylpregna-1,4-diene-3,20-dione;prednisone; dimethyl sulfoxide;N-[(7S)-5,6,7,9-tetrahydro-1,2,3,10-tetramethoxy-9-oxobenzo[a]heptalen-7-yl)acetamide];(7S,9S)-7-[(2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione;active agents capable of reacting with the amyloid P component, inparticular of bis-d-proline type, and more particularly the compound(R)-1-[6-[(R)-2-carboxypyrrolidin-1-yl]-6-oxohexanoyl]pyrrolidine-2-carboxylicacid; proteasome inhibitors, for example bortezomib, carfilzomib,marizomib, ixazomib, delanzomib, ONX-912 or revlimid; and a mixturethereof.
 49. The process as claimed in claim 46, wherein the chimericprotein is administered via intravenous, subcutaneous or intramuscularroute.
 50. The process as claimed in claim 46, wherein the chimericprotein is administered via oral, nasal, rectal or vaginal route. 51.The process as claimed in claim 46, wherein the chimeric protein isadministered via pulmonary route.
 52. The process as claimed in claim46, wherein the chimeric protein is administered via non-parenteralroute.
 53. The process as claimed in claim 46, wherein the chimericprotein is administered at a dose ranging from 0.1 to 100 mg/kg,advantageously from 0.1 to 1000 μg/kg.
 54. A method for producing achimeric protein, comprising using a starting chimeric protein asdefined in claim 30 to form a product chimeric protein comprising atleast two units, each unit comprising at least one human amyloid Pcomponent and at least one fragment of an Fc region of a human antibodybonded to each other by a hinge region, wherein the two units are bondedto each other by at least one disulfide bridge, and wherein thefragments of an Fc region of a human antibody are identical ordifferent.
 55. A method for characterizing in vitro or ex vivo thepresence of an amyloidosis deposit, comprising using at least onechimeric protein as defined in claim 30, as a tool, said chimericprotein being radiolabeled; preferably, the human amyloid P component isrepresented by 123I-SAP, and/or identified by means of a radiolabeledanti-Fc antibody; for example, said anti-Fc antibody is coupled toperoxidase.